hi guys i am medical student i visited usa in 2007 for one month on b visa for medical elective.....when i was leaving miami florida airport i handed over the "i" form to concern person and i asked him "do i need some stamp on my passport for exit" he said no need of it.. ur exit from our system he also asked my name and typed in his computer ..........now people are saying u must have exit stamp on passport to re enter usa on b visa...i am planning to give step 2 cs exam 2010 which helds in usa so i have to re enter usa on same 5 year b visa........i am really worried please help me out tht whether exit stamp needed or not?