mansion, what do you mean by that he was not a legal US RESIDENT allowed to work before he got a green card? u mean that a person in OPT (F1) takes an employment contract then it is not VALID... that person can do anything... absolutely NOT. "ur statement their is NOT TRUE". you cannot generalize such statement .. it has very many connotation hoina ra.... Imagine a scenario, a H1B gets into a contract. saying that he would be sponsored provided that he would stay with the company for 3 years after he gets his green card. Companies usually mention that this is not a commitment from the company's side that they would employe him for 3+ years.. employment contract is still HIRE AND FIRE @ will .. or depends on the contract itself... what kind of employment it is... If he is sponsored, and the company fulfills their end of the contract, then he has to fulfill his obligation i.e. stay and work for 3 years. YES HE CAN BREAK THE CONTRACT. HIS COMPANY CAN SUE HIM AND GET REIMBURSED FOR THE VIOLATION does not matter whether it is mentioned in the contract or not. I believe it would be in his/her best interest to return the cost of sponsorship. that would be reasonable thing to do if he is breaking the contract..... BUT U CANNOT SAY THAT CONTRACT IS NOT VALID.. that CONTRACT IS LEGALLY VALID. you can find similar cases in CALIFORNIA systems.. where in some employee had to bear the cost... . in some overtime payments had to be made to the employees by those consulting firms ..... NOW there are lot of things to consider, Usually reputed companies to not get to these kind of scuffle of stay longer.. or u will b charged etc.. my personal opinion .. it has to be one of the consulting firms.... owned by immigrants... now .. before you burn ur bridges... a. make sure that you have not falsified any information in ur green card application or your labor certification process. for example.... your experience, education etc... if you have make sure that you pay them the lawyer fees and get something in writing that they are not going to cancel your sponsorship or report. [ now rule is that they can RETRACT LABOR CERTIFICATION] YES. even after you get your Green Card .. sponsoring company has an obligation to report you to INS that you have left and they are no longer sponsoring you. Now if any way they can INVALIDATE YOUR LABOR. UR GREEN CARD can be CANCELLED. and THIS IS TRUE. THERE IS A PROVISION NOW..... FOR THIS.....