Background: Gallbladder ascariasis diagnosis is complicated because it depends on the location of ascaris in the biliary system, causing differences in clinical symptoms. Ascaris invasion into the ampulla of the duodenum causes a biliary colic. Meanwhile, cholangitis symptoms, such as fever, chills, and light jaundice may be present occasionally. The disease may progress into an acute cholangitis, characterized by: very high fever, chills, icterus, and upper abdominal pain. A stool examination will find ascaris eggs. The diagnosis is made by an abdomen ultrasonography (USG) examination, where an ascaris is found in the form of a circular long tubular echogenic structure. The conservative treatment includes hospitalization and anthelmintic drug administration. We report a case of gallbladder ascariasis in a 28-year-old woman with a good recovery after receiving a conservative treatment. Case: A 28-year-old woman visited our Emergency Department with a colic felt in the upper right abdomen, accompanied by nausea and vomiting, general itching, and a 10-day fever. Physical examination was positive for tenderness on the right hypochondrium on palpation. The blood test showed hemoglobin 11.2 g/dL, total white blood count (WBC) 6,200/mm3. An abdomen USG showed a picture of tubular structures engaged in the gallbladder lumen. There was no visible stone, sludge, or a fluid reflected echo in the surrounding. There was a wall dilatation, thickening, and a double (0.45 cm). Conclusions: The patient was diagnosed with gallbladder ascariasis and acute cholecystitis and hospitalized. A broad-spectrum antibiotic, an antispasmodic, and an anthelminthic drug albendazole 400 mg/day were given for 10 days. The abdomen USG on the tenth days showed the gallbladder and the biliary duct lumen were cleared from the nematode, along with the patient physical recovery.