I can't give you an answer without knowing a lot of details. You need IRS publication 590. It will tell you everything you need to know.
Go to
WWW.IRS.GOV and select information for individuals,
then resources: forms and publications; then download by publication number.
Scroll down the list until you see Publ 590. Ignore the numbers on the left of the list.
If you have never read an IRS publication before it might seem a bit intimidating. But after you get used to them they aren't to bad.