In order to elucidate the mechanism of cis-dichlorodiammine platinum neurotoxicity serial nerve conduction studies, histobiochemical and electron microscopy studies of sural nerve biopsies were done in patients receiving DDP. Three of the 10 patients treated with DDP developed sensory polyneuropathy. Histochemical and electron microscopy studies on sural nerve biopsy performed on two patients with clinical polyneuropathy have showed axonal degeneration.