For women of reproductive age, excessive gestational weight gain and/or postpartum weight retention can increase the risk of obesity. This systematic review evaluates the effectiveness of lifestyle modification control trials that utilize exercise interventions, with or without dietary intervention, on weight loss among postpartum women. A search of randomized clinical trials (RCT) was performed using the follow databases and the bibliography of candidate studies: MEDLINE, Web of Science, EMBASE, CENTRAL/Cochrane and Physiotherapy Evidence Database. English language RCT papers published up to 31 October 2012, which present changes on maternal body weight from baseline to the end of exercise intervention were included. The primary meta-analysis examined the effects of exercise interventions, with or without complementary dietary intervention, on weight loss during the postpartum period compared with usual standard of care. Five subgroup analyses were performed to examine differences in study interventions and exercise modalities: duration of intervention, quality of study methodology, supervision of exercise intervention, exercise intervention goals used and the type of dietary intervention. In total 11 studies met eligibility criteria with 769 participants, 409 under intervention and 360 in the control group. The primary meta-analysis included all 11 studies and found a mean difference (MD) on weight loss of -2.57 kg (95% CI -3.66 to -1.47). The subgroup analysis demonstrated that the most effective interventions in reducing weight in postpartum women were exercise programs with objectively defined goals, such as the use of heart rate monitors or pedometer (MD of -4.09 kg-95% CI -4.94 to -3.25, I(2)=0%) and exercise combined with intensive dietary intervention (MD of -4.34 kg-95% CI -5.15 to -3.52, I(2)=0%). Thus, there is benefit from overall lifestyle interventions on weight loss in postpartum women and exercise plus intensive diet and objective targets are the most effective intervention strategies.