Background: Coronary vessels in women may have anatomical and histological particularities. The aim of this study was to investigate sex-specific characteristics and outcomes of patients with calcified coronary arteries in the Prepare-CALC (Comparison of Strategies to Prepare Severely Calcified Coronary Lesions) trial. Methods: The Prepare-CALC trial randomised patients with severe coronary calcification to coronary lesion preparation either using modified balloons (MB; cutting or scoring) or rotational atherectomy (RA). Results: Of 200 randomised patients, 24% were women. Strategy success in general was similar between women (93.8%) and men (88.2%; p=0.27). For men, strategy success was significantly more common with an RA-based strategy than an MB-based strategy (98.7% in the RA group versus 77.3% in the MB group, p<0.001), whereas for women there was no evidence of a significant difference in strategy success between RA and MB (95.7% in the RA group versus 92% in the MB group, p>0.99, p for interaction between sex and treatment strategy=0.03). Overall, significant complications such as death, MI, stent thrombosis, bypass operation and perforations were rare and did not differ significantly by gender or treatment strategy. Plaque rupture and disrupted calcified nodules were more common in women. Conclusion: In a well-defined patient population with severely calcified coronary arteries, lesion preparation with an RA-strategy was superior to an MB-strategy in men. For women, both RA and MB strategies appear to have a similar success rate, although definitive conclusions are limited due to the small number of women in the trial.