Ovarian tumors are the second most common gynecological tumor and the fifth commonest tumor in women. Although the final diagnosis of an ovarian tumor is based on the histological examination, it is desirable to preoperatively differentiate benign from malignant tumor in order to decide whether surgery is required, and which type of surgery is appropriate. Thus, it can help avoiding unnecessary surgery, adding dynamic contrast and diffusion weighted to conventional images can help in differentiation of benign ovarian tumor from malignant. DWI depends on the fact that water molecules can diffuse freely in low cellular environment, while tissue hyper cellularity causes its restriction, a phenomenon called Brownian motion. As a result, malignant ovarian tumors due to its hypercellular nature show restriction of diffusion, unlike most benign tumors.