During a search for conserved target sequences on the genome of Coxiella burnetii for a diagnostic PCR a NotI/EcoRV DNA fragment was cloned and sequenced from the isolate "Nine Mile", Phase I (sequence data are registered under accession number X70045 in data bases EMBL, GENEBANK and DDBJ). On this fragment we have found a sequence of 1741 base pairs which showed an exceptionally high homology (60% on the nucleic acid level and 49.6% on the amino acid level) to the sporulation gene "spoIIIE" of the gram-positive bacterium Bacillus subtilis. This is first evidence of the molecular basis for formation of spores in Coxiella burnetii which has been postulated in the literature by electron microscopic investigations.