Can you give us more details?
Does it turn over? - does the engine seem to be cranking over at normal speed? Any strange noises? Is it a problem all the time, or just when the engine is cold? Once the car is running does it run ok or does it stall? Is it a standard or automatic transmission?
Anything you can add would be a help. As a rule starters are pretty reliable but there are lots of other things that can make the car hard to start.