Background:The aim of the study was to evaluate the role of posterior subtenon triamcinolone in prevention of diabetic maculopathy progression after phacoemulsification surgery. Patients and methods: Forty eyes of 30 diabetic patients with cataract and diabetic maculopathy were enrolled the study. We planned for phacoemulsification surgery followed by posterior subtenon triamcinolone acetonide (PSTA). Best corrected visual acuity (BCVA), anterior chamber reaction, and intraocular pressure were assessed at baseline and follow-up visits. Optical coherence tomography was used to assess the central subfield macular thickness (CMST), inner ring, and the outer ring thickness. Results: There is no statistically significant elevation of IOP during all follow-up visits. The mean BCVA is improved from 1.02 ± 0.12 Log MAR to 0.58 ± 0.0.01 (p = 0.0001), and 0.56 ± 0.02 (p = 0.0001), at 1 month and 3 months follow-up visits. At 6 months, BCVA is 0.42 ± 0.1 with a statistically significant difference from 1 month (p = 0.002) which is related to the progression of maculopathy. At 1 month and 3 months visits, there is no statistically significant difference in CSMT, inner ring, and outer ring from the baseline values. At 6 months, there is a statistically significant difference in CSMT and inner ring thickness as compared with the corresponding baseline values but there is no difference in the outer ring thickness. Conclusions: Combined phacoemulsification surgery with PSTA for patients with cataract and diabetic maculopathy prevents the possible progression of maculopathy in the 1 st month and the results were maintained for 3 months with good control of the inflammation even if no topical steroid eye drops were prescribed.