Objectives: Despite the benefits associated with exercise during pregnancy, many expectant mothers are inactive. Design: The present study examined whether persuasive messages could influence task and scheduling self-efficacy, exercise intention, action plans, and behavioral commitment among pregnant women. Methods: After completing premanipulation task and scheduling self-efficacy and exercise intention measures, participants (n ¼ 125) were randomly assigned to read one of four efficacy-enhancing messages: scheduling, task, combined scheduling/task, or control. Postmanipulation task and scheduling self-efficacy, intentions and action plans and behavioral commitment were then assessed. Results: Repeated-measures ANOVAs revealed that compared to the control group, inactive participants who read the persuasive messages reported significant increases in scheduling self-efficacy, task self-efficacy, and intention from premanipulation to postmanipulation as well significantly stronger action plans. Conclusions: Written persuasive messages may promote exercise behavior during pregnancy by increasing scheduling and task self-efficacy, intention, and action plans for exercise.