I came to NYC for university September 2008 but left USA for a leave of absence for a semester at June 2010. Came back to NYC on January 2011 and got issued a new visa which expires on June 2015.

I was wondering if I work for my employer starting this June:

1) Will I have to pay for social security and medicare?

2) Am I a resident or non-resident (If looking at my original visa which expires this month I have stayed here for more than 5 years but with my new visa I only stayed here for 3 years)?

2012 was your last year on F-1, so you will file as a resident in 2013.