AIM: To find out the outcome of laser photocoagulation in clinically significant macular edema (CSME) by optical coherence tomography (OCT) METHODS: It was a prospective, non-controlled, case series study enrolling 81 eyes of 64 patients with CSME between August 2008 and January 2010. All patients received modified grid photocoagulation with frequency doubled Nd: YAG laser. Each patient was evaluated in terms of best-corrected visual acuity (BCVA) and regression or progression of maculopathy after laser therapy at 1, 3 and 6 months. Spearman’s correlation test was used to show the correlation between BCVA and total macular volume (TMV). Analysis of variance (ANOVA) was used to compare among groups and independent t-test was used to compare in each group. RESULTS: There is high correlation between BCVA and TMV (P≤0.001). BCVA improved in 50.6 %, remained static in 39.5% and deteriorated in 9.9% patients after 6 month of treatment. The Baseline TMV (mean and SD) were 9.26±1.83, 10.4±2.38), 11.5±3.05), 8.89±0.75 and 9.47±1.98mm3 for different OCT patterns, ST (sponge like thickening), CMO (cystoid macular edema), SFD (subfoveal detachment), VMIA (Vitreo macular interface abnormality) and average TMV respectively (P=0.04). After 6 months of laser treatment, the mean TMV decreased from 9.47±1.98mm³ to 8.77±1.31mm³ (P=0.01). In ST there was significant decrease in TMV, P=0.01, Further within these groups at 6 months, they were significantly different, P=0.01. CONCLUSION: OCT showed the different morphological variant of CSME while the response of treatment is different. TMV decreased the most and hence showed the improvement in vision after 6 months of laser treatment. In the era of Anti vascular endothelial growth factors (VEGFs), efficacy of laser seems to be in shadow but it is still first line of treatment in developing nation like Nepal where antiVEGFs may not be easily available and affordable.