INTRODUCTION: The Leiden mutation of the factor V gene and the subsequent resistance of factor V to inactivation by activated protein C are associated with a procoagulant state, especially in the venous bed. However, its association with arterial thrombotic disease remains unclear. OBSERVATIONS: We report four patients with visual field defects secondary to arterial occlusions and in whom we found a factor V Leiden mutation. These patients, three females and one male, aged 32-58 years, presented with various visual field defects: bilateral arciform scotomas due to multiple infarcts of the nerve fiber layer (one case), superior defect due to anterior ischemic optic neuropathy (one case), homonymous hemianopia due to stroke (two cases). An abnormal resistance to activated protein C and a heterozygous state for factor V Leiden mutation were found in all four cases. The two patients who suffered from a stroke also showed elevated antiphospholipid antibodies (one case) and a patent foramen ovale (one case). COMMENTS AND CONCLUSION: Conflicting reports on the effective role of factor V Leiden mutation in arterial thrombotic events are present in the literature. We report four cases of arterial occlusion in whom a thrombophilic predisposition was present with a heterozygous state for factor V Leiden mutation. In two cases, no other risk factor was found. We hypothesize that factor V Leiden mutation, even in a heterozygous state, might predispose to arterial occlusion in some patients.