The purpose of this study was to evaluate the safety and efficacy of octreotide, a somatostatin analog, for treatment of postsurgical cystoid macular edema. Twenty-one patients with chronic, refractory postsurgical cystoid macular edema and Early Treatment Diabetic Retinopathy Study best-corrected visual acuity of 20/25 to 20/400 were randomized 2:1 to 30 mg monthly intramuscular octreotide or placebo. Outcome measures were visual acuity (primary) and macular thickness and fluorescein angiographic leakage (secondary). Fourteen eyes received octreotide and seven eyes received placebo. Mean duration of cystoid macular edema was 2.65 and 1.99 years for Sandostatin long-acting release and placebo groups, respectively. Visual acuity at 6 months improved > or =2 lines in 7 of 14 eyes (50%) in the treatment group and 0 of 7 eyes in the placebo group (P = 0.046). Improvement in retinal thickening and angiographic leakage occurred in 3 of 13 eyes (23.1%) and 3 of 14 eyes (21.4%) of the treatment group, respectively, and in 1 of 7 eyes (14.3%) (P = 1.0 compared with the treatment group) and 0 of 7 eyes in the placebo group (P = 0.52 compared with the treatment group). The three eyes that improved in all parameters were treated with octreotide. Although there were no statistically significant differences between both groups in retinal thickening or angiographic leakage, octreotide-treated patients were more likely to experience a > or =2-line improvement in visual acuity. However, this observation cannot be generalized because of the small sample size.