Aims: To correlate the severity of primary open-angle glaucoma (POAG) with diabetes (DM) and hypertension (HTN). Settings and Design: Prospective, comparative, observational study in a tertiary care centre. Methods and Material: 200 newly diagnosed POAG patients were divided into four groups of 50 patients each, Group 1 (Controls: without DM andHTN), Group 2 (DM), Group 3 (HTN), and Group 4 (DM and HTN). The worst affected eye of each patient was enrolled. The severity of POAG was based on visual field defects (VFD) on 24-2 perimetry. Statistical analysis was done using SPSS version 20 (IBM Corporation, Armonk, NY, USA). Continuous data were presented as mean±standard deviation and categorical data as percentages.Comparison between groups was performed using the Chi-Square test for qualitative and T-test or post-hoc Anova test for quantitative variables. The p-value ≤ 0.05 wasconsidered statistically significant. Results: VFD in group 2 (MD = -10.527±5.367dB), Group 3 (MD= -10.296±5.632 dB), andGroup4(MD=-12.495±7.072dB) was statistically significant (p<0.05) in comparison with Group 1(MD=-5.891±4.689). 72% of patients in Group 1 had mild VFD whereas 84% in Group 2, 82% in Group 3, and 86% in Group 4 had moderate/severe VFD. The difference was statistically significant (p<0.05). Conclusions: DM and HTN were significantly associated with the severity of POAG. Patients of POAG with DM or with HTN or with both DM and HTN had a more severe form of POAG when compared with the POAG patients without any DM or HTN.