There could be a number of reasons for leaking issues.

Repelling Issues
The first thing to consider is a repelling issue due to buildup on your diapers. Are you using a cloth friendly detergent in the correct quantity for the type of washing machine you are using? Have you used rash creams or ointments that got onto your diapers? Have you pre-washed your organic cotton or bamboo diapers properly? Check these things first:
What detergent should I use for my diapers/Can I use a store brand?
Will washing my diapers with a front load or HE machine be different?
How much detergent should I use?
Can I use diaper rash ointments and creams with my cloth diapers?
Do my diapers need to be pre-washed before I use them?

Diaper Fit
If you are sure that your issue isn't repelling, then look at the fit of your diapers on baby. Are you using a FuzziBunz® One Size diaper? If so check the adjustment of the leg elastics. Are they too loose or too tight? Often parents will over tighten the leg elastics on this type of diaper thinking that the snugger it is the better the leak protection will be. However, this is usually in fact counterproductive. If this sounds like you, try loosening the legs slightly to see if your leaking situation improves.

If on the other hand you are using a prefold diaper like the Bummis Prefolds, remember that all parts of the diaper must be contained within the cover you are using on top. Any part of the diaper left poking outside the cover can cause a leak or wick moisture onto baby's clothing. Also, do not tuck the front of the prefold into the flap sewn into the front of the cover. While this looks intuitive and handy, the flap is actually there to double over the sewing seam and prevent leaks, not to hold the prefold in place.

Diaper Material
If your diapers are made in any part with bamboo, remember that bamboo can take several washings to reach full absorbency capacity and that organic cotton needs to be pre-washed appropriately before first use.

Your Individual Baby and Parental Changing Habits
Every baby is unique, and some are just heavy wetters. If your baby needs more absorbency, and you are using pocket diapers, then use two liners in the pocket or a combination of one bamboo and one micro fleece liner in the pocket. Or add an additional liner on top of your prefolds. Adding an extra bamboo insert can work wonders without adding bulk. This is especially helpful for naps or nighttime when baby goes longer without a diaper change.

And remember, change your baby often. Babies are not meant to sit in a wet or soiled diaper for many hours at a time and frequent changing will help prevent diaper rashes too :)