Introduction: Recent studies on peripheral arterial disease (PAD) indicate prevalence of PAD in women to be equally if not greater than men, also suggesting that the latter have poorer outcomes with endovascular treatments. Hypothesis: Sex-related differences in treatment outcomes in PAD may be attributed to variations within the vessel wall. Aims: To evaluate sex-based differences in calcification patterns and lesion characteristics in PAD patients. Methods: 35 legs from 34 PAD patients (15 women) undergoing major amputation were collected. Vessels were harvested and cross-sectioned at 3-4 mm intervals, followed by histochemical staining, resulting in 1,278 arterial rings, each analyzed by an expert cardiovascular histopathologist. Results: Calcification was more prevalent in men (78.1%) than women (67.2%), though not significantly (p=0.118). The majority of calcified segments were concentric (>75% of circumference) for both men and women (66.7% and 64.4%, respectively). Women had a greater occurrence of predominantly medial calcification than men (73.3% vs. 65.3%, p=0.145). Of atherosclerotic features, men presented more fibrocalcific lesions (46.9% vs. 31.3%, p=0.023), while fibroatheroma (7.5%, vs men 4.2%, p=0.280) and fibrous plaque (10.4%, vs men 4.2% p=0.072) were more prevalent in women). In non-atherosclerotic segments, adaptive intimal thickening was more prevalent in men (37.5%) than women (16.4%, p<.001). Luminal thrombus was typically seen in women (38.7% vs. 25.0%, p=0.016), mostly presenting in an organized, chronic form in women (26.9% vs. men: 10.4%, p=0.016) and an acute form in men (6.3% vs. women: 0.0%, p=0.016). Conclusions: The localization of calcium, differences between atherosclerotic and non-atherosclerotic features, as well as the presence and form of luminal thrombus may guide treatment choices. Further studies are warranted to evaluate the impact of these differences on outcomes of endovascular procedures.