The rigid repudiation of masturbation by the Mohave Indians can be traced to their unconscious recognition of the sadistic and incestuous nature of masturbation fantasies. In spite of a free attitude toward other deviating sexual practices, they accept masturbation only in children, unmarried women and future shamans. The material of this study is derived from interviews with three maladjusted Mohave boys whose case histories were obtained with the help of a juvenile interpreter and which will be published elsewhere.