Twenty-eight VX-2 carcinomas innoculated at thigh muscles of rabbits were studied with magnetic resonance imaging (MRI) to evaluate the findings of tumors on MRI on the basis of comparison between MRI and the histopathologic findings,. magnetic resonance imaging of VX-2 carcinomas was done with a 2.0T superconducting magnet and spin-echo imaging and was done one week (14 tumors) and three weeks (14 tumors) after innoculation of tumor cells. relatively T1-and T2weighted images were obtained with REs of 500,2500 msec and TEs of 30, 80 msec. All 28 tumors were detected by MRI and showed high intensity as compared with that of adjacent thigh muscle. Intensity of tumor portions between one week group and three week group was not significantly different. Detectability of necrotic portions of the tumor was highest by T-1 weighted images with contrast enhancement and followed by T-2weighted images was best in the evaluation of nature of necrotic tissues. On T-2weighted images, low-int nsity areas corresponded to areas of early stage of necrosis, iso-intensity areas corresponded to areas of intermediate stage of necrosis, and high-intensity areas corresponded to ares of late stage of necrosis. These results suggest basic knowledge for understanding of Mr findings of tumor portion and necrotic portion of VX-2 carcinoma in rabbits.