Retinal vein occlusion (RVO) is a multifactorial disease involving vessel damage, stasis, viscosity and thrombosis. Conflicting findings on hereditary thrombophilic risk factors have been reported and their impact on RVO features remains to be defined. The aim of the present study was to evaluate the prevalence of hereditary thrombophilic risk factors (HTRF) and characteristics of RVO in patients with or without HTRF. The design of the study was a prospective, observational case series. Two hundred and thirty-four patients with RVO were included consecutively. A French healthy population of the same region was studied as control group. The HTRF studied were protein C (PC), protein S (PS) and antithrombin (AT) deficiencies, factor V Leiden (FVL) and factor II 20210A polymorphisms. Chi-Square was used for comparison with the healthy subjects and between RVO patient with and without HTRF according to localisation (branch vs. central), type of RVO (ischemic or non-ischemic), recurrence, age at first event and classical vascular risk factors. Twenty-two patients had HTRF (12 FV Leiden heterozygotes, 9 FII 20210A heterozygotes and 1 PS deficiency). No AT or PC deficiency was detected. Frequencies of PS deficiency, FVL and FII 20210A allele were similar to the reference population as well as to published data in the general caucasian population. Eighty-six patients experienced their first episode before the age of 60 years. Systemic hypertension, glaucoma and angina were significantly less frequent in patients with RVO before 60 years. Fourteen of the 22 patients with one HTRF (64%) experienced their first episode of RVO before the age of 60 years compared to 72 of 212 without HTRF (34%) (p = 0.006). Heterozygote status for FV Leiden was significantly more frequent in patients who had experienced their first episode of RVO before 60 years (p = 0.027). In conclusion, this study suggests a role of FV Leiden in the occurrence of RVO in patients younger than 60 years who exhibit fewer acquired vascular risk factors than in older patients.