Nucleic acid, ammino acid, dietary fiber, mineral and vitamin composition of six commercial inactive dried food yeasts was studied. Products A and B (autolyzed extract) were produced from Saccharomyces cerevisiae grown on cane- and/or beet molasses. Four products were produced from Candida utilis grown on calcium lignosulfate/wood sugars (C), sulfite waste liquor (D) and ethyl alcohol (E and F, autolyzed form). Levels of nucleic acids, protein, most amino acids, folacin and panthothenic acid were higher in C. utilis products than in S. cerevisiae products. Differences between dietary fiber, most minerals and biotin contents of the two species of yeast were, however, small. Autolysis and/or growth on different substrates affected levels of nucleic acids, dietary fiber and most nutrients.