SHOK (Syrian hamster Osaka-Kanazawa) cells were transfected with activated oncogenes (v-mos, c-myc, N-ras, H-ras, K-ras). These oncogene-transfected cells were treated with 195mPt-cis-diaminedichloroplatinum (II) (CDDP). Clonogenic cell survival assay showed that oncogene-transfected cells exhibited 1.3-4.8 fold (v-mos; 2.4, c-myc; 3.6, N-ras; 1.3, H-ras; 4.8, K-ras; 2.3) increased resistance to cisplatin compared with the parental SHOK cells. The distribution of DNA, RNA, and protein fractions of treated cells was determined using the method of Schneider. The CDDP concentrations binding to DNA, RNA, and protein were measured by counting 195mPt-radioactivity. CDDP uptake was decreased in these oncogene-transfected cells. However, the range of reduction of CDDP uptake in DNA was smaller than the resistance range demonstrated in the cell killing efficiency.