The sudden death of three children receiving the tricyclic antidepressant medication desipramine for behavioral disorders was reported in 1990. We now provide new information about these children and describe a fourth case. Because desipramine is a useful medication for many children, these deaths pose clinical dilemmas for physicians and families. The cardiac long QT syndrome has been proposed as a mechanism for these sudden deaths. Considerable uncertainty remains about the basis of the apparent association between the use of desipramine and the sudden deaths.