Effective immunization campaigns can be designed by determining which persuasion strategy is most effective in attracting the attention of mothers of preschoolers. The authors assess the impact of three persuasional strategies: fear-arousal, motherhood-arousal, and rational messages, on mothers of preschoolers who are late for their immunizations. The fear-arousal message was found to be most effective, followed by the motherhood-arousal, and then the rational message, in attracting mothers' attention to their child's immunization status.