Background: Gestational diabetes mellitus (GDM) is defined as glucose intolerance of variable severity, with onset or first recognition during pregnancy. GDM is associated with increased risk of poor outcomes for the pregnancy and is a risk factor for subsequent diabetes later in life. It is important to determine the prevalence and risk factors for GDM in our centre as this may influence policy formulation regarding screening and diagnosis of the clinical condition. Objectives: To ascertain the prevalence, pattern of glucose tolerance and risk factors for GDM among pregnant women attending antenatal clinic in Jos University Teaching Hospital, Jos. Study design: A descriptive cross sectional study. Materials and methods: Two hundred and sixty five (265) pregnant women were recruited by simple random sampling into the study. Patients with known diabetes were excluded. However, two hundred and fifty three (253 ) women participated in the study and were screened between 24 – 28 weeks of pregnancy with a 50g, 1- hour glucose challenge test (GCT). Those with plasma glucose concentration of >7.8mmol/l were given 75g oral glucose tolerance test (OGTT) to confirm the diagnosis. Plasma glucose measurements were performed with glucose oxidase method using a spectrophotometer (optima, model SP-100). GDM was diagnosed according to the WHO criteria. All relevant data including demographic information, obstetric history, and risk factors for GDM, GCT and OGTT results were collected for further statistical analysis.