Diabetes is a chronic, progressive disease characterized by elevated blood glucose levels. Diabetes can lead to complications such as cardiovascular disease, damage to eyes, kidneys and nerves, and premature death. Globally, more than 400 million adults live with diabetes, and diabetes directly caused 1.6 million deaths in 2015. Blood glucose management has an important role in preventing the development and progression of complications in both type 1 and type 2 diabetes. The objective of the guidelines is to provide public health guidance on pharmacological agents for managing hyperglycaemia in type 1 and type 2 diabetes for use in primary health-care in lowresource settings. These guidelines update the WHO Package of Essential NCD Interventions (WHO PEN) for primary care in low-resources settings recommendations for managing hyperglycaemia, reviewing several newer oral agents: dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors), sodiumglucose co-transporter 2 inhibitors (SGLT-2 inhibitors) and thiazolidinediones (TZDs). These agents have formerly been reviewed as first-line treatment options by the WHO Expert Committee on the Selection and Use of Essential Medicines and were not found to be superior to metformin and sulfonylurea. These guidelines consider their use as second- and third- line treatment for hyperglycaemia in type 2 diabetes. The guidelines also present new recommendations on the selection of type of insulin (analogue versus human insulin) for adults with type 1 diabetes and in adults with type 2 diabetes for whom insulin is indicated. WHO PEN recommendations on other aspects of diabetes treatment have not been updated because priority was given to the area where the majority of changes in evidence and practice have occurred since the publication of WHO PEN. The guidelines were developed in accordance with the WHO Handbook for Guideline Development. In brief, the WHO Steering Group, in collaboration with the Guideline Development Group, developed key questions and rated outcomes to identify those critical for the guideline development. Systematic reviews of the evidence were used to build Summary of Findings tables according to the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) methodology. The Guideline Development Group developed recommendations, considering the strength of the evidence; the balance between desirable and undesirable effects; resource requirements and costeffectiveness; health equity; acceptability (including patient preferences); and feasibility.