Purpose: This study aims at investigating possible associations of P-selectin polymorphisms with proliferative diabetic retinopathy (PDR) in Yazd, Iran. Methods: The subjects of the study included of 55 PDR and 55 diabetic no retinopathy (DNR) cases attending Yazd Diabetes Research Center (YDRC). P-selectin genotyping was done by an ARMS-PCR method. Results: The P-selectin variants rs6128, rs6133, and rs3917779 were not in Hardy-Weinberg equilibrium. The frequency of the rs3917779 C allele ( P < 0.0001), but not the rs6133 G allele ( P = 0.19) or rs6128 allele ( P = 0.20), was higher in PDR cases than in control DNR cases. Significant differences in the distribution of rs3917779 ( P < 0.001), but not rs6128 ( P = 0.52) or rs6133 ( P = 0.18), genotypes were observed between cases and controls, and only rs3917779 showed a significant association with PDR, with increments of 49.2 (14.72-125.07) in disease risk seen for CC genotypes. Among the eight three-locus P-selectin haplotypes constructed (rs6128 / rs6133 / rs3917779), there was no significant difference between frequencies of haplotypes in the DNR and PDR groups. Conclusions: P-selectin gene polymorphisms and haplotypes can contribute to PDR development. [ABSTRACT FROM AUTHOR]