AP Ezreal. Good burst, powerful mid game champ, late game support. Guide meant for people who wish to try out AP Ezreal; this is the build I've been running, and it's the most successful. Not implying AD Ezreal is inferior or superior, the guide is strictly a tool for people who want to enjoy Ezreal. Also, AP Ezreal was the first build that made me believe he can be very powerful. This is my first guide, so hopefully it's easy on the eyes. I will update the rest of this guide later. Feel free to comment, but be polite about it ;)

Leona patch
AFAIK, Ezreal has remained untouched other than having a minor AP ratio added to his Q. Nothing totally big, it just makes his Q hit a bit harder (having 200 ap adds 40 more damage)

I have updated items to make it more consistent for the current meta.

v1.0.0.112

Ezreal
Trueshot Barrage now scales with bonus attack damage at a 1.0 ratio

AP Ezreal is now probably truly outshined by AD Ezreal with Trueshot Barrage being ridiculously powerful now. Well, anything AP enthusiasts, AP Ezreal hasn't been touched.

Pros:
Powerful Burst
Essence Flux is more than useful
Fun ^_^
Ulti does a lot in team fights
Good AP Ratios

Cons:
Sustained DPS is inferior to AD Ezreal
****py mobility without triforce
Farming is weak, as Mystic Shot scales with AD and Ezreal's other spells are terrible for farming.

I always mix and match one offensive and one defensive. My preference is Exhaust/Flash.

My favorite summoner spell, did not really deserve its nerf. I run this on AD Ezreal too. Not exactly mandatory. Good throughout the game as it pops burst output and slows enemies. Defensive AND Offensive.

Good early game, bad late game for damage. Use this if you think it'll help you get kills/first blood. Also good alternative to Exhaust. Offensive.

Ok, use this. Just do it, and you'll find yourself not dying. Defensive

Same as flash, but if you like running (kiting, w/e) then you might prefer this. Defensive

Meh. Not great on Ezreal. Use it if you love it. Offensive/Support

Anything else isn't particularly useful on Ezreal. Clarivoyance should be run on support, but you can take it if you like being aware.

Standard Caster Runes. Mix and Match. Note that these are the runes I run, so you can go and do whatever you want on your page. These are my justifications for why I use them.

Greater Mark of Magic Penetration - No other Mark beats this for casters. You can try out other marks, but I would just stick with this one for Ezreal

Greater Seal of Scaling Mana Regeneration - Recent nerfs may have made them not as good as before, but it's still good cause base mana regen of champions have been increased. I don't buy a lot of Seals, so experiment with other runes if you wish to try out an alternative.

Greater Glyph of Scaling Ability Power - Give your essence flux some oomph. Not ideal for beginners.

Greater Glyph of Cooldown Reduction (Alternative) - Versatile and good buy. Ideal if you are buying for your first rune page. Somewhat useful on Ezreal, but his mystic shot decreases CD anyways.

Greater Glyph of Scaling Mana Regeneration (Alternative) - Also a good pick for those who like to spam spells.

Greater Quintessence of Ability Power - More oomph, 15 AP level 1. Need I say more?

Greater Quintessence of Health (Alternative) - Ideal for beginners, nerfs have not put it out of viability. Doran's ring is still a poor choice for most casters, imo.

9/0/21. Standard Caster Masteries. I advise using Greed, Awareness, Intelligence, Quickness, and Archaic Knowledge. Others can be mixed around for preference

R>W>E>Q

Farming Ability. Can harass with it if you want. Just shoot it off at minions when you can't last hit them. Note that it is terrible mid-late game without lichbane. Use it anyways, just because it procs lich bane. Note that casting it procs and uses lichbane.

Your damage ability. The range of the particle is a little bit more than it appears. Goes through minions and enemy champs, and debuffs/boosts AS of enemies and allies respectively. Hurts a lot early game if you got the mana for it. Otherwise, don't be too spammy with it.

*** Saving Ability. Or your "Kassadin" ability. Use it for either, the cooldown kind of sucks, so make sure you can get a kill or save your life when using it. Otherwise, it's kinda dumb to use it for anything else. Does decent damage at least and a somewhat reliable nuke, makes your kiting very powerful. CAUTION: You can semi-stun yourself if you E into a wall. It's like a bug, so be very careful. I'm not totally sure if it will happen, but it does occasionally. Also, Arcane shift does not dodge particles, so you will get stunned if you dodge a stun or any other cc.

Global ulti, with lower cooldowns than most other ultis. Super powerful in teamfights. Landing it is a bit tough, as it takes a sec to cast it. I'll get in depth in aiming this skill later.

Please note I have revised the recommended items

*new*
Start off with a Doran's ring, this will aid your early game burst by a lot. If you have trouble in the lane get another ring and a tear + boots. Ring is more priority if you do have trouble. After tear, immediately rush Deathcap because you absolutely need the AP. If you find yourself low on mana (which is a bit odd if you have a tear and a ring) then grab blue buff. After Deathcap get Lich Bane. Your absolute core is Tear+Deathcap+Lichbane. It is ridiculously expensive but because AP Ezreal is so outshined by other AP carries, you have a lot of make up for.After lich bane get void staff or finish archangel's.

*old*
Explanations for items I recommend:

Tear of the Goddess - Gives Ezreal much needed mana and mana regen. Unlike AD Ezreal, AP Ezreal can deplete mana quite quickly. You can turn this into an Archangel's if you are doing relatively well. is a good item on Ezreal, unlike its AD counterpart which kind of sucks on AD Ez.

Mejai's Soulstealer - Core on AP Ezreal. Why? Similar to Kassadin, Ezreal can net assists/ganks quite easily and has very good survivability. I'm a hater on snowball items, but I feel AP Ezreal is really dependent on this item. If you just plain can't maintain your stacks above 7 or so,you might as well sell it. It's cost effective at 4 stacks, I believe, but your item slot can be used for something else if your game is no good. If you are also not a fan of stack items or just don't want to run this, skip it and go to sheen.

Boots - Turn this into either Ionian or Sorcerer Boots. Merc treads if you want, but I feel merc treads are a bit useless seeing as how Ezreal is squishy.

Lich Bane - Core. Grab a before/after/instead of mejai's. Lichbane will add a lot to your burst as it procs ON Mystic Shot. Now you have a full burst arsenal. Note that Lich Bane IS physical damage. Useful if the enemies aren't stacking armor.

Rabadon's Deathcap - Raw AP, and lots of it.

Banshee's Veil - Generally a good item to grab on anyone. Especially useful if the enemies have mild-heavy cc and have a lot of AP. Important that you get this if you are struggling. Note that when getting a defensive item on an offensive champion you are not compromising your damage output.

Other Items:

Rylai's Crystal Scepter - This is a decent item, gives a slow (bit negligible), health, and AP. I wouldn't rush this for any reason.

Void Staff - Grab it if the enemy team is stacking MR. Also a good item overall.

Zhonya's Hourglass - Good item overall. If you like the active, go for it.

AP Ezreal needs farm or ganks. Mid is the preferable lane, but AP Ezreal isn't much of an AP carry, imo, so if someone else could utilize mid, give it to them. You want to focus on last hitting as much as possible. However, when the enemy is caught off-guard, you can harass with Essence Flux. Try to farm up enough for a Tear and boots before you port back. Always grab a ward, it will save your life.

Solo Laning: Ezreal can get harassed quite easily, so you may want to get a point in E early. Just last hit as much as possible. The more aggressive champions I recommend you do not engage. On another note, AP Ezreal can be an aggressive laner like his AD counterpart IF you have the mana to keep it up. Many times I have noticed enemy laners who deplete their mana trying to harass me, and that's when I go in for the kill.

Duo Laning: Same advice as solo laning. However, you are fully capable of keeping up aggression with your lane partner. Just don't get focused.

Early Game - You have potential in getting ganks. If you can get some, go for it. You need the moneys. Shoot your ulti into other lanes to help out fights, the cd is quite low. I advise you not to roam. Defend turrets if your team is being pressed on.

Mid Game - You should have your core and a decent amount of AP and stacks on your mejais. If you are struggling at this point, ditch mejais and get lichbane and archangels. This part of the game is where you shine, kill the squishys. Try to get as many stacks as possible, and carry your teammates. You want to win at this point of the game.

Late Game - SOTL. If your team straggled and turtled this far, you will be quite lackluster. Ezreal overall is not a late game champion. Ward the map as much as possible. Stick with the tanks. Note that if you have a great amount of AP and a lichbane, you will destroy turrets.

Don't initiate, don't be at the frontlines. You aren't a tank. Jump in mid fight, land your ulti before so if possible to scare the enemies. E in, use W and Q. Simple as that. Leave no man alive, and try to kite if possible. If you have lich bane, Q hits really hard. And because it's physical, enemy mr will not be a factor.

Well, that's all I have to say about using AP Ezreal. Maybe if I'm not lazy, I can get some screenshots in. Also, I haven't played AP Ezreal in a while, but his stats haven't been hit since the last time I've played him. I hope you enjoyed this guide and AP Ezreal.