Arterial dissection is one of the mechanisms of balloon angioplasty. Although some degree of dissection is unavoidable, severe dissection that impedes blood flow decreases patency and increases the need for additional procedures. To improve the results of angioplasty, it is necessary to understand the factors related to severe dissection and make efforts to reduce its occurrence. This study aimed to elucidate the predictive and protective factors associated with severe dissection in femoropopliteal balloon angioplasty. This was a retrospective, single-center, nonrandomized study. A total of 409 limbs were studied in 334 patients with symptomatic femoropopliteal lesions treated between 2010 and 2019. Dissections after initial balloon angioplasty were classified according to the Kobayashi dissection classification (grade A: no dissection; B: mild dissection <1/3 of the lumen; C: severe dissection, ≥1/3 of the lumen) into the nonsevere dissection group (grades A and B), and severe dissection group (grade C). We compared clinical, procedural and lesion-related characteristics between the 2 groups. Factors with statistical significance in univariate analyses were entered into a multivariate logistic regression model to identify independent predictive factors of severe dissection. Severe dissection occurred in 237 limbs and nonsevere dissection in 172 limbs. In univariate analyses, the predictive factors of severe dissection were TransAtlantic Inter-Society Consensus II C/D grades (P < 0.001), lesion length ≥15cm (P < 0.001), chronic total occlusion (P=0.004), and degree of stenosis ≥70% (P < 0.001). Protective factors for severe dissection were end-stage renal disease (P=0.008), severe calcification >50% (P < 0.001), and the use of a scoring balloon (P=0.001). In multivariate analysis, factors associated with severe dissection were lesion length ≥15cm (OR, 2.259; 95% CI: 1.417-4-3.601), occlusion or degree of stenosis ≥70% (OR, 1.931; 95% CI: 1.255-2.971), severe calcification (OR, 0.520; 95% CI: 0.338-0.800), and the use of a scoring balloon (OR, 0.467; 95% CI: 0.263-0.830). Lesion length ≥15cm and occlusion or stenosis ≥70% were identified as independent predictive factors of severe dissection in femoropopliteal artery balloon angioplasty. Conversely, severe calcification and the use of a scoring balloon appeared to be protective factors against severe dissection.