The DNA sequence was determined for a region upstream of the puf operon of Rhodospirillum rubrum. A partial ORF was identified. The DNA sequence and the inferred amino acid sequences were aligned with those of bchA of Rhodobacter capsulatus and other phototrophic bacteria. Based on this alignment and genetic evidence, this ORF was identified as R. rubrum bchA, which encodes an enzyme involved in bacteriochlorophyll biosynthesis. An additional ORF was identified in the intergenic region between bchA and pufB. Sequences possibly having a role in puf expression were identified.