Background:Treatment of severe acute pancreatitis can be challenging with high mortality. In 2012 we reported a significantly reduced in-hospital mortality if these patients are treated conservatively for at least the first 3 weeks in the course of the disease as compared to early necrosectomy. We performed a long-term follow-up and compared the outcome of these two study groups (group 1 – early necrosectomy,n=20 versus group 2 – primary conservative treatment,n=24).Materials and methods:Follow-up of the study patients by personal contact, phone survey, or data from primary care physician. Median follow-up was 15 years (range 10–22 years). This trial is registered at: Research Registry UIN researchregistry8697.Results:Eleven survivors of group 1 and 22 survivors of group 2 were discharged after initial treatment. Ten of 11 surviving patients of group 1 (90.9%) and 20 of 22 surviving patients of group 2 (90.9%) were included in this study. Between groups, there were no statistical differences in the rate of resubmission (P=0.23), development of diabetes (P=0.78), or development of exocrine insufficiency (P=1.0). However, long-term survival in group 2 was significantly better than that of group 1 (P=0.049).Conclusion:Primary conservative treatment of severe acute pancreatitis without early necrosectomy does not lead to early complications and even shows an advantage in long-term survival. Therefore conservative treatment of severe acute pancreatitis is safe and there is no absolute need for necrosectomy in severe acute pancreatitis.