The hyperproduction of alkaline and neutral proteases is a phenotype of mutation at the hpr locus. This locus has been cloned and sequenced and has been found to code for a protein of 23,718 Mr. The mutations hpr-1, scoC4, and catA7 were identified by sequencing as mutations within the hpr gene. The phenotype of mutations in the hpr gene is due to loss of the hpr gene product, and therefore we suggest that the hpr gene encodes a negative regulator of protease production. This negative regulator must control genes other than protease genes, and these genes must include at least one gene required for sporulation, since overproduction of the hpr gene product by cloning the locus on a multicopy vector results in the inhibition of sporulation as well as protease production. Truncated fragments of the hpr gene or its promoter do not have this phenotype. Transcription of the hpr locus is controlled by the spoOA gene. In an spoOA mutant the hpr gene transcript is constitutively overproduced, as determined by a transcription fusion to beta-galactosidase. The results are consistent with the view that the spoOA gene may control sporulation and transcription by modulating the level and activity of several regulatory proteins.