It absolutely depends on the yoga! I've taken yoga classes that were intense strength training all by themselves. I would not be able to do an effective resistance training routine on the same day. However, if it's more of a slow, relaxing yoga, then there's no reason you can't do it on the same day as any other exercise.
Can you do yoga and strength training on the same day?
Also, can you do yoga and cardio on the same day?
Why or why not?
If no, how long should you wait between sessions?
Yes you can--what you don't want to do is two times a day weight training or cardio. It's best to take one day off or *every other day when it comes to weight training so your muscles repair better. Since Yoga is more stretch it won't interfere with your weight or aerobic--unless you are doing a very difficult yoga class?