 × complex, ژaal-sirkar, medical college and hospital, polgata. First objective. To evaluate the impact of ژaal-brother ژal-thickness on the outcome of laparoscopic cholecystectomy, rate of conversion to an open procedure. Introduction. Biliary disease constitute a major portion of digestive tract disorders. Among these, gallstone disease is the most common biliary pathology. Prevalence of in India has been estimated to be around three to five percent. Philippe Moret in funds firstly introduced laparoscopic colosistectomy in 1987. Since then, minimal invasive surgery still evolving. It has rapidly replaced open colosistectomy as the standard treatment. Laparoscopic colosistectomy is considered as the treatment of choice in colelithiasis. Ultrasonography is the initial imaging method for diagnostic approach and evaluation of the biliary system as it is widely available, non-invasive and non-expensive. Ultrasonography has been able to reliably detect gallstones in greater than 90 percent of symptomatic patients and the measurement of the thickness of the gallbladder wall by ultrasound is accurate to within one mm in 93 percent of patients. There are zero to 20 percent conversion rates in local and international studies and in number of studies gallbladder wall thickness more than three mm on ultrasound has been shown to have a positive relation with an increased conversion rate to open colosistectomy. Materials and method. This is a prospective clinical study that was conducted in the department of radio diagnosis at Nilratan Sirkar Medical College and Hospital Kolkata. Between 1st of December 2022 and 13th of July 2023, 185 percent were included in the study. We recorded patients' ASA system illness and operative nodes and performed pre-operative ultrasonography with logic P9 ultrasound machine in Christian criteria. All patients 18 to 70 years with features of chronic calculus colosistitis electively prepared for laparoscopic colosistectomy were included in the study while in exclusion criteria patients who had previous upper abdominal surgeries pregnant patients patients with carcinoma of gallbladder and common wild dark stones patients with features of acute colosistitis also excluded. All patients were evaluated by hematological and biochemical investigations like CBC, blood sugar, liver function test, kidney function test, bleeding profiles, ESR. Sonography of the biliary system done after keeping the patient on fast for at least 8 hours. The wall of gallbladder was carefully evaluated and is considered as thick when its thickness is greater than 3 mm. These sonographic findings were re-verified by the surgeon in the operating room. All patients under a laparoscopic colosistectomy which was done using close method with four ports. The difficulty in procedure which resulted into conversation where one or more of the following that is adhesions involving the callous triangle excessive bleeding from gallbladder bed while dissection. In this table we see that sex distribution among study population. There are a total of 185 cases included in the study of this 42 cases were male and 143 cases were female. The male female ratio was 1 is to 3.40. In this table we evaluate the gallbladder wall thickness by ultrasonography. In the overall 138 cases had a gallbladder wall thickness less than 3 mm while 47 cases had a gallbladder wall thickness greater than 3 mm. In this table we evaluate the gallbladder wall thickness and type of surgery. In the overall data set of 185 cases 138 cases had a gallbladder wall thickness below 3 mm while 47 cases had a wall thickness exceeding 3 mm. Among them 47 cases 17 of them went into conversion. In this table we evaluate the accuracy of gallbladder wall thickness more than 3 mm in predicting the need of conversion of laparoscopic cholecystectomy to open cholecystectomy in patients with cholelectasis. And in the results we found that the sensitivity was 63.80% specificity was 100% and accuracy was 90.81%. In discussion laparoscopic cholecystectomy has become the gold standard treatment of symptomatic gallstone. A gallbladder wall thickness on preoperative ultrasound represents the presence of inflammation or fibrosis due to previous attacks of cholecystitis. Conversion from a laparoscopic cholecystectomy when open cholecystectomy is an intraoperative decision by the laparoscopic surgeon when visualization and identification of the operative anatomy is invoked. Anatomy is impaired by increased vascularity from the inflammatory response dense adjacent edema fibrosis or abnormal anatomy such as short cystic duct or an intrahebatic gallbladder. In this image we see that gallbladder wall with thickened wall that is greater than 3 mm adjacent encounter intraoperative reading to conversion of laparoscopic to open surgery. Based on findings of present study, gallbladder wall thickness significantly helps to determine the difficulty during surgery and resulting into higher conversion rates. We found that an increased gallbladder wall thickness greater than 3 mm in 47% resulted in conversion into open procedure in 17% A study by Muntajke Hanna at all found that 512% hoped. 1350% had increased gallbladder wall thickness more than 3 mm in 22% of them converted to open polycystectomy. A study by Pawan at all found that 24% out of 73% had difficulty in laparoscopic surgery and 17 of them were converted to open surgery. Also a higher conversion rates in our study would be attributed to the multi-phase attacks of acute cholecystitis that the patients suffered before reporting to the hospital as is the trend generally in India. Thickened gallbladder wall was identified as a risk factor for difficult laparoscopic cholecystectomy in many studies and Sarmayatoll also concluded that gallbladder wall which is 3 mm and thicker significantly makes more difficult dissections of gallbladder. In conclusion we see that meticulous operative re-operative diagnostic technique is mandatory to provide information for a rational selection of the most effective treatment for polylithiasis and to avoid intraoperative difficulty and suffrage. Presently in our settings ultrasonography is the morality of choice for measuring gallbladder wall thickness because it is economical, easily available, radiation free and non-impressive with accuracy of 92%. Need to convert is neither a failure nor a complication but an attempt to avoid complication which has to be kept in mind by the surgeon. Thank you.