I've found that my chicken dries out when I overcook it.  I couldn't understand how chicken could become dry, in a slow cooker with chicken broth, tomatoes, veggies and a ton of liquid, and then I found out I was cooking it too long.

Boneless skinless breasts don't need to cook as long as breasts with a bone in.

Start by reducing the time for 15 minutes from what you are doing now.  I cook 4 split breasts on 350 for about 40 minutes.  It really all depends on the size/thickness of the breast, some are much thicker then others.

Good luck!

Robbyn     

Hi,  You may want to try baking the chicken at a higher temputure.  I bake chicken at 425 - 450 degrees.  Cooks faster and stays moist.  If yoy would like to boil or stew you chicken, I bring the skinless, bonless chicken breasts into a tall pan or a pot.  Just cove with water and season to taste.  I use kosher salt, pepper, cinamon, celery seed and italian seasong.  Cover, bring to a boil, reduce heat, low boil for 10 minutes, turn off the fire.  DO NOT LIFT THE LID.  Let sit for a little while.   The chicken will be moist and full of flavors.  Use what ever seasonings you enjoy.  The broth that is left over is great for soups, stews, sauces etc.    

Good luck!!  ENJOY!!

hOPE THIS HELPS

Aside from whatever sauce/marinade I use to baste the chicken, I also had water to the pan.  I cook chicken in a glass pie pan at 375+ degrees for about 30 minutes.  It never dries out.

This might sound really absurd, but when I bake chicken I always marinate the chicken with Kraft Fat Free Italian Dressing.  I don't know if it is the acidity of the dressing or what it is, but it will honestly be the most moist chicken you will ever bake!  When you marinate it with the dressing it doesn't matter how you prepare it -- it always comes out moist.  Hope it works well for you, too!  I haven't found anything better.

Brining!

Brining works in accordance with two principles, called diffusion and osmosis, that like things to be kept in equilibrium. When brining meat, there is a greater concentration of salt and spices outside of the meat (in the brine) than inside the meat (in the cells that make up its flesh). The law of diffusion states that
the salt and sugar will naturally flow from the area of greater concentration (the brine) to lesser concentration (the cells). There is also a greater concentration of water, so to speak, outside of the meat than inside. Here, too, the water will naturally flow from the area of greater concentration (the brine) to lesser concentration (the cells). When water moves in this fashion, the process is called osmosis. Once inside the cells, the salt and, to a lesser extent, the spices cause the cell proteins to unravel, or denature. As the individual proteins unravel, they become more likely to interact with one another. This interaction results in the formation of a sticky matrix that captures and holds moisture. Once exposed to heat, the matrix gels and forms a barrier that keeps much of the water from leaking out as the meat cooks. Thus you have meat that is both better seasoned and much more moist than when you started.

I usually do a mixture of .25 cup salt to 1 quart of water. This is a great article on brining meats!

The same thing happened to me until I decided that it was worth the money to buy some organic chicken. Now it always stays juicy. :] I'm not like, necessarily promoting that all of yall should now buy organic food. It's just that I've been partly raised on a Russian farm as a kid, and well, my grandma's chicken there was as good as it got (it's half the reason I go back every summer). When I moved to the states and we baked chicken, it always came out dry until we switched to organic. It's a lot more expensive, but nevertheless tastier and juicier.

You could also try putting onion and tomato slices below the chicken when you bake it. My mom and I do that for baking fish to keep it moist, but you could try doing it for chicken as well.

covering your pan with tin foil for the first half of baking will help keep the moisture in.  also pour some marinade or water in the pan with the chicken to keep it from drying out.  Remember to take the foil off for the top to brown a little, if that's important to you.  hopefully this helps :)

I agree with Annie, if you can find it buy organic or SMart Chicken...they do something different to it, like flash freezing or something and it keeps it SO moist and SO tender.  Also if you buy Kosher Chicken it's already been brined so it's very flavorful and moist.  Also you may want to invest in a meat thermometer.  THat way if you are also shortening your cooking time you can still make sure the optimum temp has been reached to kill any bad stuff lurking in your chick.

You're probably keeping it in the oven too long, like msrobbyn said.  Reduce the time and cut into a piece to check if its done.