Gestational diabetes mellitus (GDM) is a common condition with risks for mother and baby. Type 2 diabetes mellitus (T2DM) and obesity are occurring with increasing frequency, and the incidence of GDM reflects this trend. Further, new diagnostic criteria have greatly increased the prevalence of GDM. Potential lifelong consequences exist for mother and baby if the condition goes untreated; however, adverse maternal and fetal effects can be ameliorated by effective pregnancy management. The aim of this article is to provide practical advice regarding GDM diagnosis, management and postpartum follow-up for general practitioners, who, increasingly, will be involved in GDM care. Controversy surrounds many aspects of GDM. Recommendations are frequently based on consensus. In the context of a deficient evidence base, any recommendations are open to debate. However, it is reasonable to suggest a pragmatic way forward, maintaining an open mind about the current diversity of practice and a preparedness to include further research findings into future practice.