Mutations leading to decrease or absence of orthophosphate-repressible acid phosphatase activity have been studied. It is shown that these mutations can arise in three genes: acp1, acp2 and acp3, which are not linked. Genes acp1 and acp2 have been studied previously; the existence of the gene acp3 is demonstrated in this paper. It is established that all mutations in the acp3 gene are recessive, are leaky and epistatic to the constitutive mutations in all known regulatory genes for acid phosphatase II synthesis - acp4, acp80, acp81, acp82, acp83, and acp84. The gene acp3 is not linked with these regulatory genes, but it is closely linked with the structural gene for constitutive acid phosphatase - pho1 (D=0.33+/-0.20 cM). The pho1 gene has been recently located on the right arm of chromosome II on the left of the gene lys2. Mutations lacking activity of constitutive and repressible acid phosphatases simultaneously have been found. It is shown that these mutations are allelic to mutations in the gene acp3 and pho1 simultaneously. Two hypotheses are proposed about the role of the gene acp3: the gene controls the positive factor for the repressible acid phosphatase synthesis or the structure of the enzyme.