Introduction: Surgery for chronic pancreatitis involves ductal clearance, identification of cystic lesion and  mass lesion. Intra operative ultrasonogram (IOUS)  is   useful  in surgery for chronic pancreatitis. Aim:  To analyze and assess the impact IOUS in  drainage surgery for chronic pancreatitis.Methods: IOUS was performed in patients  with chronic pancreatitis(GpI) compared with control group wit out IOUS (Gp II) which were similar  . The outcome measures  were  analyzed and compared.  Stastical analysis: SPSS 14 version was used, student t test, chi square test, Fiser exact probability test were used appropriate. P value of  <0.05 was considered  significant. Results: IOUS proved beneficial in identifying intra ductal calculi, undrained cyst ,  identification of pseudoaneursym, mass lesion and  to do IOUS guided FNAC i. Conclusion: Clearance of ductal calculi, drainage of cyst  was more complete with IOUS (Gp I) and  found to be  useful  in  patients undergoing drainage surgery for chronic pancreatitis.