An investigation was made of the extent to which mental operations involved in quantitative conservation and pretense play affect the development of gender constancy. The research design included three phases: a pretest establishing subjects' levels of conservation and gender understanding, a training phase, and conservation and gender constancy posttests. Following pretests, nonconserving subjects were randomly assigned to one of three treatment conditions: (1) a conservation training condition stressing principles of identity and reversibility; (2) a pretense play training condition using inquiry procedures based on techniques described by Golomb, Goransen-Gowing, and Friedman (1982); and (3) a control condition which engaged subjects in drawing pictures. A total of 33 preschool children 4 or 5 years of age participated in the study. Overall, results supported the contention that similar cognitive operations underlie conservation of quantity, pretense play, and gender constancy. (RH)