To evaluate the effects of topical timolol on lipid profile, blood samples from 25 patients (16 males and 9 females) were analysed before topical instillation of 0.5% timolol maleate and thereafter at one month and two months. After two months of therapy, the level of high density lipoprotein (HDL) decreased significantly (p < 0.02). The levels of low density lipoprotein (LDL), very low density lipoprotein (VLDL) and triglyceride increased but the changes were not statistically significant. Since low level of HDL is strongly associated with increased risk of myocardial infarction, our study cautions use of topical timolol in patients with low levels of HDL or with previous history of coronary heart disease.