Gallbladder agenesis (GA) is a rare congenital malformation characterized by the absence of the gallbladder and cystic duct due to an anomaly in the embryonic development. It is commonly associated with other congenital abnormalities, and the isolated form is extremely rare. Its clinical presentation is variable. Actually, GA is more often incidentally diagnosed. Magnetic resonance cholangiopancreatography (MRCP) is considered to be the diagnosis method of choice since it avoids unnecessary and risky surgery in symptomatic patients. Here we report the case of a radiologically incidentally discovered gallbladder agenesis in a 68-year-old patient.