Purpose: 123I-labeled fatty acids have been used in the evaluation of regional myocardial energy metabolism. This study aimed to evaluate the usefulness of 123I- BMIPP as a liposarcorna-imaging agent. Materials and Methods: We compared in vitro uptakes between liposarcoma(SW872) and glioma(9L) cell lines, and examined biodistribution and in vivo images of 123I- BMIPP in liposarcoma-bearing nude mice. Cold-BMIPP was labeled with 123I using Cu2+ as catalyst. After purification by Sep-pak, radiochemical purity was determined by TLC. We compared cellular uptake between glioma and liposarcoma after incubation of 5, 10, 15, 30, 60, 120, and 180 mins with culture medium containing I-BMIPP. The difference in biodistribution was determined between non-feeding (water only) group for 18 hr and feeding group in normal mice (n=6/group) at 0.5, 2, and 24 hr. In liposarcoma-bearing nude mice model, liposarcoma, SW872, cell lines were injected subcutaneously into the left thigh of nude mice. The biodistribution of 123I-BMIPP was evaluated at 0.5, 2, and 24 hr (n=5 / group) and in vivo image of 123I-BMIPP was obtained with gamma camera at 2 and 24 hr in liposarcorna-bearing nude mice. Results: Radiolabeling yield and radiochemical purity were 95% and above 99%, respectively. SW872 cell line showed more increased uptake than 9L with 1.5 times at 180 mins. The clearance of 'I-BMIPP in various tissues was more delayed in the non-feeding group than in the feeding group, especially at delayed time (24 hr) in normal mice, and the major excreting organ was the gastrointestinal tract. In liposarcoma-bearing nude mice, tumor/blood ratio of 123I-BMIPP was 0.94, 0.75, and 1.38 and tumor/muscle ratio was 0.66, 1.53, and 1.11 at 0.5, 2, and 24hr, respectively. 123I-BMIPP was selectively localized in liposarcoma at 24 hr image. Conclusions: These results suggest that 123I-BMIPP can be used as a liposarcoma-imaging agent. (Korean J Nucl Med 200135:324-333)