Wet ashing of K562 cell suspensions by means of a sulphonitroperchloric acid digestion for electrothermal atomic absorption spectrometry of platinum has been achieved. The limit of detection was about 1 ng platinum per 10(6) cells. Platinum concentrations in K562 cells were measured after exposure to platinum coordination complexes such as cis-dichlorodiamminoplatinum (DDP) and Trans-1 diamminocyclohexanooxalatoplatinum (1-OHP). Cell linked platinum was measured after a 24 hours exposure to a concentration of 6.8 nM ml-1 of both forms 1-OHP and DDP (i.e. 1.3 micrograms platinum per ml). Platinum concentrations were found to be respectively (mean +/- S.D.) 14.8 +/- 2.7 and 10.0 +/- 4.0 ng platinum per 10(6) cells. These 1-OHP and DDP concentrations were cytotoxic and about twenty times the 50 percent cell growth inhibitory concentrations (0.45 nM ml-1 and 0.33 nM ml-1 respectively).