Cholecystitis is an inflammation of the gallbladder caused by obstruction of the cystic duct. A gallstone usually causes the obstruc­tion (calculus cholecystitis). However, in some cases the obstruction may be acalculous or caused by sludge. The clinical course of biliary sludge varies, from complete resolution to gallbladder obstruction. This obstruction can result in gallbladder distension and acute cholecystitis. When inflammation occurs it could either be aseptic or bacterial. Biliary disease during pregnancy is relatively rare and occurs mainly during the last trimester. Whether women who are pregnant or have multiple pregnancies are more likely to develop stones or whether they are simply more symptomatic with stones is unknown. We present a 33-year-old obese pregnant woman with fever, moderately elevated bile acids, and leukocytosis in the 28th week of pregnancy. Since need for surgery in these cases is controversial, the patient has been treated conservatively. In our case cholecystitis responded very well to treatment with amoxicillin, with no detrimental effects for mother and child. A healthy child was born at term. In the differential diagnosis of liver function abnormalities during pregnancy, cholelithiasis should be included.