QUESTION: Does exercise improve postprandial glycaemic control in women diagnosed with gestational diabetes mellitus? DESIGN: A systematic review of randomised trials. PARTICIPANTS: Pregnant women diagnosed with gestational diabetes mellitus. INTERVENTION: Exercise, performed more than once a week, sufficient to achieve an aerobic effect or changes in muscle metabolism. OUTCOME MEASURES: Postprandial blood glucose, fasting blood glucose, glycated haemoglobin, requirement for insulin, adverse events and adherence. RESULTS: This systematic review identified eight randomised, controlled trials involving 588 participants; seven trials (544 participants) had data that were suitable for meta-analysis. Five trials scored ≥ 6 on the PEDro scale, indicating a relatively low risk of bias. Meta-analysis showed that exercise, as an adjunct to standard care, significantly improved postprandial glycaemic control (MD -0.33mmol/L, 95% CI -0.49 to -0.17) and lowered fasting blood glucose (MD -0.31 mmol/L, 95% CI -0.56 to -0.05) when compared with standard care alone, with no increase in adverse events. Effects of similar magnitude were found for aerobic and resistance exercise programs, if performed at a moderate intensity or greater, for 20 to 30minutes, three to four times per week. Meta-analysis did not show that exercise significantly reduced the requirement for insulin. All studies reported that complications or other adverse events were either similar or reduced with exercise. CONCLUSION: Aerobic or resistance exercise, performed at a moderate intensity at least three times per week, safely helps to control postprandial blood glucose levels and other measures of glycaemic control in women diagnosed with gestational diabetes mellitus. REGISTRATION: PROSPERO CRD42015019106. [Harrison AL, Shields N, Taylor NF, Frawley HC (2016) Exercise improves glycaemic control in women diagnosed with gestational diabetes mellitus: a systematic review.Journal of Physiotherapy62: 188-196].