We reviewed the cases of 27 young children from 27 different families who were suffocated by their mothers. The certainty, or near certainty, of suffocation was based on reliable observation or recording of the suffocation, maternal confession, or successful prosecution in a criminal court. Eighteen of the children are alive, although one has severe brain damage; nine are dead. Twenty-four were reported to have had previous episodes of apnea, cyanosis, or seizure, and 11 had had 10 or more such episodes that were either invented or caused by the mother. Repetitive suffocation usually began between the ages of 1 and 3 months and continued until it was discovered, or the child died, 6 to 12 months later. The 27 children had 15 live elder siblings and 18 who had died suddenly and unexpectedly in early life; 13 of the dead siblings had had recurrent apnea, cyanosis, or seizures, and, although most of them at the time of death were certified as having sudden infant death syndrome, it is probable that some were suffocated. Repetitive suffocation has a characteristic clinical presentation that should allow identification before brain damage or death occurs. The characteristics should also allow the cause of death of some cases of sudden infant death to be established more accurately.