Background and Objective: Gallstones represent a significant public health problem in modern societies, affecting 10% to 15% of the adult population. The types of gallstones include mixed, cholesterol and pigment stones. This study was aimed to evaluate the serum lipid profile and common bile duct diameter in patients with gallstones pre-operatively and post operatively and to establish the effect of cholecystectomy on lipid profile and common bile duct dimensions. Materials and Methods: The study was conducted in Narayana Medical College and Hospital, Nellore, Andhra Pradesh, India. This was a prospective observational study carried out from August 2019 to March 2020. Results: Out of total 50 cases, 29 cases (58%) were female and remaining 21cases (42%) were male.Highest number of cases were in the age group 30-40 years (38%) followed by 30% between 40 to 50 years of age.In the present study, there was decrease in Total Cholesterol levels, Low density lipoprotein (LDL) and Very low density lipoprotein (VLDL) levels 1 week after surgery, 1 and 3 months after surgery. Triglycerides (TG) levels initially increased after 1 week and decreased significantly 1 and 3 months after surgery. Significant increase in HDL levels are seen after 1week which continued till 3months after surgery. The current study showed an significant increase in CBD diameter of 0.53, 0.76 and 1.07 mm in 1week, 1month and 3 months respectively after surgery. Conclusion: It can be concluded from this study that cholecystectomy results in normalization of lipid levels.And also increases the diameter of Common bile duct but within physiological limits of that age and sex group