We studied the effect of anti-cancer chemotherapy including cis-platin (CDDP) on renal high uptake of 99mTc-MDP using renal accumulation index (RAI) which was defined as a ratio of the densities between kidneys and lumbar bodies. We analyzed 21 cases who received bone scintigraphy within 30 days after chemotherapy. High RAIs were observed in 15 cases (71.4%). We compared the relationship between the RAI and time interval of CDDP administration and bone scintigraphy, total dose of CDDP, BUN and age. High RAIs were inversely related to the time interval and no patient showed high RAI when bone scintigraphy were studied later than 17 days after chemotherapy. BUN level were related to RAI. But, dose of CDDP and ages were unlikely responsible for the RAI values in this study. We summarized that high renal uptake of 99mTc-MDP was likely to be due to short time interval after chemotherapy.