Objective This study tested the effectiveness of a pedometer program for increasing physical activity levels and reducing body weight in overweight and obese mothers of young children. Design Participants’ motivational readiness to exercise, exercise self-efficacy, pedometer steps, pedometer kilocalories, and anthropometrics were evaluated at week 0 and week 8; anthropometrics were reassessed at week 24. Healthful-weight mothers provided comparison data at baseline. Subjects/setting A convenience sample of 93 intervention women (body mass index [calculated as kg/m 2] ≥25) and 31 comparison women (body mass index <25) were recruited from public health clinics, community centers, and churches. Eligibility criteria included Hispanic, African-American, or white ethnicity and low income (<200% of the federal poverty index). Intervention An 8-week physical activity and dietary program was conducted. Main outcome measures Motivational readiness to exercise, exercise self-efficacy, pedometer steps, and weight loss. Statistical analyses performed Independent sample t tests, χ 2 tests, paired t tests, Wilcoxon signed-ranks tests, repeated measures analysis of variance, and Pearson and Spearman correlations. Results Mothers enhanced their motivational readiness to exercise, exercise self-efficacy, pedometer steps, and pedometer kilocalories. Reductions in body weight, percent body fat, and waist circumference also were observed. Significant correlations were found between exercise self-efficacy and exercise readiness ( r=0.28, P<0.01), pedometer steps ( r=0.30, P<0.01), and pedometer kilocalories ( r=0.28, P<0.05). Conclusions This intervention successfully increased the physical activity levels and promoted weight loss in low-income mothers. Public health clinics may wish to incorporate elements of this intervention into their programs to improve the physical fitness of recipients.