Hypoglycaemia is a feared experience for people with diabetes. We aimed to study the prevalence and causes of hypoglycaemia among Sri Lankans with diabetes.One thousand patients with diabetes attending a private sector diabetic clinic were interviewed using a structured questionnaire. Hypoglycaemic episodes within the preceding month were inquired and severity was graded according to clinical features and/or capillary blood glucose levels.Mean age 55.0 years (± 12.5), 58.6% were males, mean diabetes duration 10.6 years (± 8.1), mean FPG 7.48 mmol/l (± 2.79) and mean HbA1c 7.82% (± 1.71) (62 mmol/mol). Of them, 26.1%. (mild 20.7%, moderate 3.9%, and severe 1.5%) experienced symptomatic hypoglycaemia. Sudden change diet (46.7%), unaccustomed exercise (15.7%) and increase in antihyperglycaemic therapy dosage (14.9%) were the recognized causes. Cause was not recognized by 16.3%. Non-prescribed native food items accounted for hypoglycaemia in 16.9% of patients (Momordica charantia 54.5%, Costus speciosus 52.3%, Salacia prinoides 11.4%, Coccinia grandis 6.8%, Adenanthera pavonina 4.5%). Severity of hypoglycaemia was positively correlated to age and duration of diabetes but not to HbA.Hypoglycaemia is common among patients with diabetes. Patients need advice on regular diet and exercise. Consumption of non-prescribed native foods should be considered as a possible cause.