Objective:-Primary open angle glaucoma (POAG) is a major cause of blindness in the world. Elevated intraocular pressure (IOP) is a major proven risk factor for glaucomatous optic neuropathy and has been shown to be associated with metabolic diseases, such as diabetes mellitus and hypertension. The aim of the present study was to evaluate the association of fasting blood glucose and HbA1c with IOP in POAG patients with and without diabetes mellitus. Materials and Methods: - 40 patients of POAG with and without diabetes mellitus were included. Patients receiving IOP lowering treatment and other ocular diseases were excluded. Control group comprised of 45 age and sex matched individuals without glaucoma. Fasting blood glucose and HbA1c were estimated by using commercially available standard kits. Results: - Fasting blood glucose (FBG) levels were found significantly higher in POAG patients with (115.33+7.42) and without (93.41+ 5.82) diabetes mellitus as compared to the control (90.27=11.76). HbA1c level was significantly increased in diabetic (9.75+/-1.64) and non diabetic (6.8+/-0.98) POAG patients than control (6.01+/-0.94). Mean IOP significantly raised with elevation of HbA1c levels in POAG patients. FBG (r=+0.51, r=+0.55 respectively) andHbA1c(r=+0.73, r=+0.71 respectively) levels were significantly correlated with IOP in POAG patients with and without diabetes mellitus. Conclusion: - These findings indicate that FBG and HbA1c are associated with increased IOP in POAG patients with and without diabetes mellitus. We conclude that disturbances of glucose metabolism could play a role in glaucoma damage and pathogenesis and monitoring of HbA1c and fasting blood glucose with IOP in glaucoma patient is helpful to be made to assess the magnitude of damage.