This study examined the pattern of drug use in an elderly population aged 70 years and over, and the factors associated with drug use. The study population was selected by stratified random sampling of all registered recipients of Old Age and Disability Allowance in Hong Kong. 997 men and 1,035 women were interviewed as part of a survey on physical, functional, mental health and social status of the elderly in Hong Kong. 71% of the sample took drugs, the prevalence being higher in women. The most common drugs taken were antihypertensives, skin preparations, vitamins and minerals, other cardiovascular drugs, antacids or H2 antagonists, and non-steroidal anti-inflammatory analgesics (all over 10%). Overall, 66% were using medications that were unlabelled. Factors associated with drug use that were examined included socioeconomic factors, educational level, physical health, cognitive function, depressive symptoms, functional ability, life satisfaction, and living arrangements. Multivariate analysis using forward step-wise logistic regression showed that the use of prescription drugs was associated with the presence of chronic disease, poor self-perceived health and being female. Use of > 5 drugs was associated with similar factors: presence of chronic disease, being female, and residence in institutions. The factors for use of non-prescription drugs were different: living in the community, presence of joint pain restricting activities, dissatisfaction with living arrangements, and age. Reducing the number of unlabelled drugs, restricting access to non-prescription drugs, improving access to doctors and patient education all might well be important measures in improving the therapeutic needs of this elderly population.