The Bacillus subtilis 168 chromosomal region extending from 184 degrees to 195 degrees, corresponding to prophage SPbeta, has been completely sequenced using DNA of the thermoinducible SPbetac2 mutant. This 134416 bp segment comprises 187 putative ORFs which, according to their orientation, were grouped into three clusters. Compared to its host, SPbetac2 is characterized by a lower G+C content, shorter mean ORF length, as well as a different usage of start codons. Nearly 75% of predicted ORFs do not share significant homologies to sequences in available databases. The only highly similar proteins to SPbetac2-encoded ones are host paralogues. SPbetac2 promoter regions contain SOS box consensus sequences and a repeated motif, designated SPbeta repeated element (SPBRE), that is absent from the host genome. Gene sspC, encoding the small acid-soluble protein C, that has been previously sequenced and mapped to the vicinity of the SPbeta region, was found to be part of the prophage.