Nutrition therapy is an integral part of the management of gestational diabetes mellitus (GDM). Four leading nutrition and diabetes organizations, the Canadian Diabetes Association (CDA), Dietitians of Canada (DC), Diabète Québec (DQ), and the Ordre professionnel des diététistes du Québec (OPDQ), formed a partnership to develop evidence-based nutrition practice guidelines for the management of GDM. It was generally agreed that nutrition requirements during pregnancy are similar for women with or without diabetes. However, evidence supporting current nutrition therapy practice specific to these clients remains limited. Nutrition recommendations for the management of GDM provided here are built on the available evidence and the principles, practices and treatment goals of the Canadian Diabetes Association 2003 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada. They identify areas where additional research is needed to support optimal nutrition therapy.