Background: Data on sex-related outcomes of pulmonary vein isolation (PVI) of cryoballoon ablation (CBA) in atrial fibrillation (AF) are sparse. Aim: To compare sex-differences in PV reconnection, strategy and outcome of repeat ablations after CBA. Methods: Repeat procedures were performed using radiofrequency ablation guided by 3D mapping. PV reconnection characteristics were compared in 229 patients (77 (33.6%) females). In durable PVI patients, we compared left atrial voltage maps, ablation strategy and 1-year outcome. Clinical success was defined as freedom of documented AF or atrial tachycardia (AT) >30s. Results: Female patients had a lower overall number of PV reconnections (0.8±0.9 vs 1.2±1.0, P<0.001) driven by less reconnected left PVs: 13/77 (16.9%) vs 51/152 (33,6%), P=0.008 and 7/77 (9.1%) vs 39/152 (25.7%), P=0.003 for LSPV and LIPV, respectively. Durable PVI was more frequent in women (34/77 (44.1%) vs 37/152 (24.4%), P=0.001). Female sex was the only independent predictor for durable PVI (HR=2.003; 95%CI 1.090-3.682; P=0.025). In durable PVI patients, substrate ablation was more frequently performed in women (21/35 (60%) vs 13/35 (37.1%), P=0.044), mainly targeting the higher prevalent atrial low-voltage zones (21/35 (60.0%) vs 12/36 (33.3%), P=0.017). At 1 year, recurrence of AF/AT did not differ between sexes: 6/35 (17.1%) vs. 8/35 (22.9%), P=0.591. Conclusions: The higher persistence of durable PVI in women points to a sex difference in AF recurrence driver after CBA. In durable PVI patients, a higher prevalence of low-voltage regions results in more substrate ablation in women. Despite sex differences in ablation strategy, 1-year outcome was similar.