I have a cement floor in my basement, lately I have noticed dark spots on the floor. Is it possible that water is coming up from the ground underneath. I know there are no water lines or sewage lines under the floor also the spots are in the middle of the floor and not by any outside walls. The spots are also getting bigger. If there is water coming up does anyone know what kind of contractor to call.

My only guess is that you may need a sump pump which I believe you would start with a plumber.

Hydrostatic Pressure in a liquid (http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/Pressure/HydroStatic.html)

Thanks smearcase for your answer, I will be calling a plumber on Monday. I just don't understand why It just started these past few months because I lived in this house for 19 years.

In the area I live in, we have gotten about 15 inches of rain compared to droughts the last 5 to 10 years. We have cut the grass 12 times now and for the past two years, we cut the grass 5 times for the entire season. We are on track for cutting 4 times as much.
Also, if you have had grading and/or development or other heavy work, it can change the patterns of underground water even if it's a long way off, but the surface water (rainfall) is the most likely cause. I'm betting you'll find that rainfall in your area is above average.

There's another answer to ground water intrusion beside installing a sump pump and that would be to install a french drain,(see image) around the basement walls to carry the water away from your house. If you're interested in a french drain Post over on the Plumbing Page and we'll discuss it farther. Regards, Tom