Although verbalization of cognitive processes is a common strategy in the study of clinical decision making, the effect of verbalization on performance has not been adequately assessed. The effect of verbalization of cognitive processes on performance on a computer-assisted clinical simulation was examined using a three-group experimental design. Sixty pediatric nurses were randomly assigned to one of three groups (n = 20/group): instructions to think aloud, instructions to recall decision processes, or no instructions to verbalize. The experimental groups did not differ on proficiency or efficiency scores on the computerized clinical simulation. Two-way analyses of variances revealed no main or interaction effects when examining type of verbalization instructions by level of education, years of pediatric experience, or case familiarity, suggesting that there was no apparent effect of verbalization of cognitive processes on performance regardless of level of expertise. These findings support the continued use of verbalization of cognitive processes as a strategy to examine clinical decision making.