Aim: To assess changes in macular thickness after uncomplicated cataract surgery in diabetic patients using optical coherence tomography. Material and Method: The present prospective observational study was conducted in the department of Ophthalmology. As this is a time bound study, we recruited minimum of 50 eyes in each group. Patients were further divided into two groups: GROUP A: Known case of Type 2 Diabetes Mellitus (DM) and Patients having fasting plasma glucose (FPG) of more thanor equal to 126 mg/dl or a 2-hour post prandial plasma glucose (PPBG) of more than or equal to 200mg/dl. GROUP B: Patients with no past history of type 2 DM and Patients with FPG less than 126mg/dl or PPBG of less than 200mg/dl. Results: Before the surgery, mean foveal thickness (optical coherence tomography) among the diabetic subjects was 252.35±11.21which increased to 311.45±14.31post cataract surgery. Before and after the cataract surgery, mean foveal thickness (optical coherence tomography) among the non- diabetic subjects was 229.42±7.53which increased to 265.46±5.73 post cataract surgery. Pre-operatively there was no significant difference among group A and B w.r.t. mean foveal thickness as p>0.05. Post-operatively (2 month) mean foveal thickness increased more in group A (study group) as compared to group B (control group) with statistically significant difference. Mean logarithm of minimal angle of resolution visual acuity (optical coherence tomography) among the diabetic subjects was 0.85±0.07 which decreased to 0.39±0.15 post cataract surgery with statistically significant difference. Before the surgery, mean logarithm of minimal angle of resolution visual acuity (optical coherence tomography) among the non- diabetic subjects was 0.79±0.07 which decreased to 0.21±0.08 post cataract surgery with statistically significant difference. Conclusion: Diabetic individuals present a specific difficulty since they are prone to developing cataracts at an early stage and are more likely to have retinal edema and the advancement of retinopathy after undergoing cataract surgery. Uncomplicated phacoemulsification leads to an increase in central macular thickness in both diabetic and nondiabetic patients.