In this study, new free fluid segmentation method is proposed, aiming to increase segmentation accuracy on free fluids, at the same time, decrease processing time, regardless of the accuracy of initial seeds. In order to segment free fluid regions fast and accurate, we propose a new free fluid segmentation based on Chan-vese level-set with an improved initialization using minimum variance region growing. The proposed method is devised to take complementary effects on both methods. In experiments, the effectiveness of the proposed method is demonstrated with 3D US volumes in terms of Dice’s coefficient, volume difference, Hausdorff distance and processing time. Results show that the proposed method outperforms CVLS and MVRG in terms of processing time as well as segmentation accuracy.