AbstractA balance of ATP‐consuming processes in human erythroleukemia (K 562) cells by use of the decreased14CO2formation from [1‐14C]‐glutamate following inhibition of energy‐requiring processes is presented. This method was tested on Ehrlich mouse ascites tumour cells and was used in suspensions of K 562 cells with a low cell content. More than 90 per cent of the ATP produced by oxidative phosphorylation could be accounted for in K 562 cells. Protein synthesis consumed about 35 per cent, Na+/K+‐ATPase about 20 per cent and transcription processes 5–10 per cent of the total ATP. The share of the Ca2+‐dependent reactions was notably high at 25 per cent in comparison with Ehrlich mouse ascites tumour cells, reticulocytes or hepatocytes. ATP consumption by DNA synthesis was assessed at 5–10 per cent. Only less than 10 per cent of the consumption of ATP produced oxidatively remained for other cellular reactions. The degree of coupling of K 562 cells was high in comparison with that of other eukary