In 20 out of a series of 30 children with Bourneville's disease, the diagnosis was made from the association of epilepsy and multiple achromic spots, before the appearance of adenomas. A total of 27 of these 30 children had these spots, and their characteristics are reviewed, as well as the average age of onset and frequency of the other typical cutaneous signs noted in this group: sebaceous adenomas, Koenen's tumors, and leather-grained skin plaques. Severe epilepsy was a constant finding and was often resistant to treatment: West's syndrome (18 cases), and Lennox Gastaut's syndrome (16 cases). Severe mental deficiency was also an almost constant finding and was increased by behavioural disorders: 11 out of the 13 children aged more than 5 years. Other locations of the disease included more particularly the ocular (8 cases), skeletal (11 cases), and renal (1 case) regions. In 5 cases, the disease had been transmitted by a parent, but in 3 of these it had not been recognized.