Hi I am an international student from africa graduating in US.college has quarter system of 2.5 months session each time.I have just completed first quarter.I need to vist my country for a month.will that effect my F1 status and will I be able to reenter USA?the college says that its is possible to take a leave for next quarter but I still doubt of US immigration laws

You can maintain F-1 if you don't leave US for a period of over 5 months plus your I-20 must be valid. Talk to international office at your school... you may need your current I-20 endorsed before you leave.

You are not eligible to leave the US until you have completed a full academic year. In your case your international advisor at school should be able to submit you for an authorized absence on your I-20. You won't be able to return (be reinstated) until after the end of the term you are leaving in. Your international advisor has all this info, or can find it out.