The atp gene region of Clostridium acetobutylicum DSM 792 has been fully sequenced. It contains the F0F1 ATPase genes in the order atpIBEFHAGDC, whose products share high sequence homology to the respective proteins of a variety of other bacteria. It is the first such sequence available for a mesophilic Clostridium. Significant differences to other reported atp operons are a distal transcription start point 219 bp upstream of the translation start point and a second transcription initiation site (without corresponding promoter sequence) upstream of atpE, indicating posttranscriptional processing for massive expression of this gene product.