This is a report of a case of lower-abdominal linea alba hernia in a 65-year-old woman. The patient was 152cm in height and 125kg in weight with the body mass index (BMI) of 54, showing serious obesity. She had noticed abdominal distention since 5 years earlier, but let it alone because she was asymptomatic. She was seen at the hospital because a hernia around the umbilicus was pointed out at a medical checkup. A computed tomography showed a hernia that derived from a defect in the abdominal wall. A portion of the intestine protruded from the defect and was incarcerated in the subcutaneous lesion. An operation revealed a defect in the abdominal wall on the lower median part of the abdomen, and the contents of the hernia were the transverse colon and the omentum. Lower abdominal linea alba hernia was diagnosed, and the hilus of the hernia was closed. Linea alba hernia is a rare condition, and 68 cases have been reported in Japan. Furthermore, a hernia in the lower abdomen is extremely rare, and only nine cases, including this one, have been reported in Japan. All of the patients were female. We considered that weakness of the linea alba due to abdominal high pressure by obesity and/or a history of the maternity might be the main cause of lower abdominal linea alba hernia.