To assess levels of compliance in elderly patients on timolol eyedrops for glaucoma.A postal questionnaire was sent from the general practitioner to 86 patients over 55 years of age on repeat prescriptions for timolol eyedrops. The questionnaire asked details about the duration of treatment, family history, the level of understanding of the disease and the importance of treatment, other regular medication, side-effects attributed to the drops and how often patients omitted their drops. A search of practice and local hospital dispensing data was carried out to assess how frequently monthly repeat prescriptions for timolol eyedrops were dispensed over a 12 month period. This allowed a total volume to be calculated for each patient.Twenty-four per cent of patients admitted to omitting eyedrops either occasionally or frequently. Fifty-one per cent were found to have had insufficient drops dispensed to comply with treatment as prescribed. In non-complaint patients the mean period without drops was 85 days of the year, with a maximum of 165 days.Compliance with treatment is poor and patients underestimate their level of defaulting when questioned.