Aims: This parallel group randomized controlled trial assessed whether an SMS reminder system for women, after gestational diabetes, would increase their attendance for an oral glucose tolerance test (OGTT) by six months postpartum. Methods: Women were eligible for inclusion if they were diagnosed with gestational diabetes in their recent pregnancy, had a mobile phone and normal blood glucose profile prior to postnatal discharge from the Women's and Children's Hospital, Adelaide. A computer-generated random number sequence and telephone randomization were used. Two hundred and seventy-six women were randomized. Women in the six-week group (n = 140) were sent a text reminder to attend for an OGTT at six weeks postpartum, with further reminders at three and six months if required. Women in the control group (n = 136) received one text reminder at six months postpartum. Blinding was not feasible. The primary outcome was OGTT attendance within six months postpartum. Results: Women in the six-week group did not increase their attendance for an OGTT within six months postpartum compared with women in the control group, 104 (77.6% of 134) versus 103 (76.8% of 134), relative risk (RR) 1.01, 95% confidence interval (CI) 0.89-1.15. Conclusions: The SMS reminder system did not increase postpartum OGTT, fasting plasma glucose or HbA 1c completion, although high rates of test completion were measured in both groups. Further research is required into factors influencing attendance for postpartum testing from the perspective of women, and into optimal counselling relating to Type 2 diabetes risk in the postpartum period for increasing postpartum glucose testing rates. What's new?: Women who have had gestational diabetes often do not have postpartum screening for Type 2 diabetes, despite their increased risk. Therefore, it is important to research methods for improving postpartum diabetes screening. This is the first published randomized controlled trial examining the efficacy of SMS reminders for increasing postpartum screening for Type 2 diabetes in women who have had gestational diabetes. Our research found an overall higher rate of postpartum screening for Type 2 diabetes than many previous studies. However, women in the six-week SMS reminder group were no more likely to complete diabetes testing than women in the control group.