Introduction: As off pump Coronary artery bypass grafting surgery (CABG) is a developing method in coronary cardiac surgery, most surgeons are anxious about the danger of emergency crash conversion. In this observational study we tried to show the rate and outcome of conversion . Material and methods: In this descriptive study about 477 coronary off-pump CABG patients were operated in Ghaem hospital in Mashhad, Iran, from Jan 2012 to Jan 2013.In this group 20 patients needed to convert to Cardiopulmonary Bypass (CPB) immediately .We analyzed these 20 patients and produced the results. Results: There was no cerebrovascular accident (CVA) and no neurologic problems.There was one death among these 20 patients. There was one case of renal failure who was the same patient that expired. 75% of these 20 patients had hypertension and 45% had diabetes . Conclusion: 20 patients (4.19%) had an emergency switch to On-pump CABG and only one death occurred among 20 patients