background: This dosimetric study aims to evaluate the dosimetric advantage of the irregular surface compensator (Isc) compared with the intensity-modulated radiotherapy (IMrT). Materials and methods: Ten patients with whole breast irradiation were planned with the Isc and IMrT techniques. six different beam directions were selected for IMrT and Isc plans. The treatment plans were evaluated with respect to planning target coverage, dose homogeneity index (DhI) and organs at risk (Oars) sparing. Monitor units (MUs) and the delivery time were analysed for treatment efficiency. results: The Isc technique provides a better coverage of the pTV and statistically significantly better homogeneity of the dose distribution. For the ipsilateral lung and heart, Isc and IMrT techniques deliver almost the same dose in all plans. however, MU counts and delivery time were significantly lower with the IMrT technique (p < 0.05). conclusion: For breast radiotherapy, when the Isc method was compared to the IMrT method, Isc provided better dose distribution for the target.