Abstract Background Severe calcification, assessed using the peripheral artery calcification scoring system (PACCS), is associated with poor clinical outcomes after endovascular treatment (EVT) for de novo femoropopliteal lesions. However, the PACCS classification is a qualitative assessment performed in the angiographic room, and there are no established indicators for the quantitative assessment of calcification prior to treatment. Purpose We aimed to investigate the impact of the lower extremity arterial calcification score (LEACS) calculated using non-contrast lower limb computed tomography on clinical outcomes after drug-coated balloon angioplasty for de novo femoropopliteal artery disease. Methods We retrospectively analyzed the clinical outcomes of 141 consecutive patients treated at our center for de novo femoropopliteal artery disease using a drug-coated balloon between April 2018 and December 2022. Patients who did not undergo lower limb computed tomography before EVT were excluded from the analyses. LEACS was determined based on the method used to calculate the Agatston score for the coronary arteries. Each patient’s score consisted of a sum of calcification scores from ostium of superficial artery to the popliteal artery at the knee joint of treated limb. The primary and secondary outcomes measured were primary patency and clinically-driven target vessel revascularization (CD-TVR) at 1 year. Cox proportional hazards analysis was used to explore independent predictors of clinical outcomes. The study population was divided into higher and lower LEACS groups based on the cut-off value (1750), which best discriminated patency, and the outcomes were compared between the two groups. Results In the higher and lower LEACS groups, the mean age was 75.1 ± 9.1 years and 75.5 ± 11.0 years (p = 0.87) and the mean lesion length was 170.3±102.8 mm and 157.7±112.1 mm (p = 0.64), respectively. The higher LEACS group showed significantly lower 1-year patency than the lower LEACS group (53.5% vs. 84.3%, log-rank, p = 0.041). In addition, freedom from 1-year CD-TVR was significantly lower in the higher LEACS group than in the lower LEACS group (66.8% vs. 93.7%, p = 0.047). The Cox proportional hazard analysis showed that the higher LEACS group was an independent predictor of 1-year restenosis (odds ratio: 2.80, 95% confidence interval: 1.24–8.84, p=0.037), along with a small (< 5 mm) reference vessel diameter (odds ratio: 3.55, 95% confidence interval: 1.44–9.53, p=0.028). Conclusion Higher LEACS scores were independently associated with clinical outcomes after drug-coated balloon angioplasty for de novo femoropopliteal artery disease. Non-contrast lower limb computed tomography is an acceptable and feasible option for predicting the outcomes in patients with de novo femoropopliteal artery disease prior to treatment.