Gallstones have been shown to develop in patients who experience rapid weight loss after dietary restriction and bariatric surgery . Data regarding gallstone development after Sleeve Gastrectomy, however, are limited. The aim of this study was to evaluate the incidence of gallstones formation after laparoscopic sleeve gastrectomy as a common complication to rapid weight loss during one year period after operation.40 patients had been followed up after undergoing bariatric surgery for assessment of gallstone formation and results found according to sex, age, DM, hyperlipidemia, type of surgery, relation to BMI, rate of weight loss, timing of gallstone formation. The mean age of patients was 37 . and 27 patients were females (67.5%). Half of patients came with morbid obesity (BMI from 35 to 40), and the other half with extreme morbid obesity (BMI >40). After one year of Sleeve Gastrctomy operation 8 patients developed gallstones while 32 patient were free from gallstone formation. According to sex, 5 females developed gallstones After one year of Sleeve Gastrctomy operation, while 2 males came with the same diagnosis, p= 0.27, According to age, 4 cases Less than 40 y. presented with gallstone formation After one year of Sleeve Gastrctomy operation, while 3 cases More than 40 y. came with gallstone, p=0.75. Gallstones are a common complication after rapid weight loss from laparoscopic sleeve gastrectomy. Routine prophylactic cholecystectomy is recommended for weight reduction during laparoscopic sleeve gastrectomy.