I put this guide together because I love playing Dr. Mundo in the jungle. I also play him top sometimes in certain matchups. Dr.Mundo is really fun as he doesn't use mana but his own life to fuel his abilities. He has nice slow, can deal damage and is naturally tanky due to his normal builds and Ulti. Will really appreciate any input to improve these guides. Masteries might need some work and will appreciate feedback on this. The start and core builds work well - the situational items - well again this will probably change as the season 3 meta develops and as I figure the new items out. This by no means a definitave guide on Dr. Mundo - just something that reflects my playstyle. I got silver in season 2 so not a high end player by any means :)

Will add sections later on why chose certain runes, masteries etc pros cons and all the rest to make this a proper guide. For now let me know how I can improve it please! And please vote for my guide if you like it and give a reason if you down vote it - Thanks!
Enjoy!

Updates
[2012-12-24 changed masteries + item order + items]
[2013-01-10 changed item order + items]
[2013-01-15 Added jungle map and routes]
[2013-01-15 Pros and Cons]
[2013-01-15 Added some items]
[2013-01-15 Added item discussion and summoner spells]

Still to Do
Masteries and runes
Counter jungling and ganking
Expand on spells and items list

Works well with Dr. Mundo as this with his Ulti Maximum Dosage makes it almost impossible to run away from him or to catch him.

Is the obvious one for any jungler.

Other Choices:

Is also an option but i prefer Ghost as with Maximum Dosage you can cover any distance very quickly
Also not bad choice - you already have movement steroid with Maximum Dosage so taking this instead of Ghost is an option and can help make ganking more effective

Infected Bonesaw Use to poke, initiate ganks and when playing top this is what you use. Nice slow and range.

Heart Zapper an AOE spell that drains your life while dealing damage around you. Remember to switch off when low health or not in combat....

Blunt Force Trauma Improves your AD damage for 5 seconds and increase it more for every 1% of health missing. With agony draining health and this your attacks get stronger the lower your health.

Maximum Dosage Regen your life and a 12 second movement steroid. Use this to chase enemy down, run away or for sustain in jungle.

Start Items:

The start items are quite standard for junglers in S3: Hunter's Machete + 5 Health Potion.
This enable you to do first clear quite fast with enough health to do blue,wolves,wraiths,golems,red,wraiths,wolves on the first clear before have to go back and have about 650+ gold.

Early game items:
On first back you will need to decide on getting Spirit Stone or Boots. I usually get Boots + Rejuvenation Bead + some more Health Potion. This then builds into Spirit Stone on the next back and gives you a little health regen in the meantime.

Mid Game items:

This is where it starts to get tricky. The item order etc depends on how you did in early game, how your team is doing, what is the enemy team composition etc.

By this time you will have your ulti which gives you good sustain so you can stay in the jungle for quite a while. If things go well I will try to get 1000 gold before going back and get my Giant's Belt. With Giant's Belt you can solo dragon from lvl 7 onwards. Giant's Belt also builds into both Warmog's Armor or Spirit of the Ancient Golem depending on your needs. If not enough gold you can get your Ninja Tabi. In S2 you built Mercury's Treads on Mundo but with the Tenacity from Spirit of the Ancient Golem you don't need this anymore and can rather get Ninja Tabi as they give extra armor that helps in the jungle. The magic resist you can get from Spirit Visage. If you have spare gold take Ruby Crystal or another Rejuvenation Bead as they build into your Warmog's Armor. Extra Health Potion or sight ward are also always handy.

By the end of the mid game you should have completed your Warmog's Armor, Spirit Visage, Spirit of the Ancient Golem and Ninja Tabi. This will give you lots of health, health regen, come CD and 35% tenacity to help against Mundo's bane - Ignite and other CC. This coupled with Maximum Dosage and Ghost makes it very difficult to kill Dr. Mundo. From this point onwards if you play smart you will almost never die anymore.

End Game:

There are a number of items that can be considered in the end game:


This is what I usually go for - 700 extra health + a slow to make Mundo even more tanky With Infected Bonesaw and Frozen Mallet this is nice item that gives health and burns the target for damage. This item I'm still considering for Dr. Mundo. If you get early lead then this will give you some good extra attack damage. If you go this route make sure to build Avarice Blade early as it will help pay for itself.
Very situational - if they have an AD heavy team and ADC that is fed - this will help you.
Gives health, slow and AP - what is not to like about this item?
Again health, and a slow . If you need armor build this, if want more AP build Rylai's
If your support is not building it and the enemy is AP heavy then this will help you and your team Works well on mundo but if I build it I usually sell it later for something with more health, damage etc... If the enemy team Ignite the **** out of you then get this item, can sell it later when more tanky. Also gives 45 MR
AP, MR and reduce MR of enemy - all will help you do more damage

More Speeeeeeddd !!!!
Land cleaver, speed up - cool!
More for support but helps your team if they run to you
Help to get quicker back to fight if need to return. (can help if in base defending....)

Pros + Very fast jungle. + Strong counter jungling. + Extremely tanky in the right situations. + Surprising damage output. + Goes where he pleases.

Cons - Only one CC that also hits minions. - Deals a ton of damage to himself. - Drops easily with Ignite and CC. - Might goes where he pleases but not always where it please his team

This is the jungling routes I use most often:

If playing with random team start at Blue (1) for the XP (I know Mundo don't need mana but the XP and cooldowns reduction helps him getting into the game quicker - 2nd blue onwards are all donated to mid/team) and ask for team to help damage ,then go Wolves (2) , Wraiths (3), Golems (5) do red buff (4) , wraiths again (3) . You should now be lvl 4. You can now either do wolves (2) again if have enough health or go back. While first clear is fast you will have no health pots left and be low health. Be careful to check bushes before doing red to make sure not getting counter jungled.

If with team you know can start at Wolves (2) then do Blue (1) and follow normal route.
Starting Wraiths (3) then Red (4) is also viable on Mundo - can then give first blue to mid if someone with mana issues.