To sequence the entire 800 kilobase pair genome of the bacterium Mycoplasma pneumoniae, a plasmid library was established with contained the majority of the EcoR1 fragments from M.pneumoniae. The EcoR1 fragments were subcloned from an ordered cosmid library comprising the complete M.pneumoniae genome. Individual plasmid clones were sequenced in an ordered fashion mainly by primer walking. We report here the initial results from the sequence analysis of -56 kb comprising the dnaA region as a potential origin of replication, the ATPase operon and a region coding for a cluster of ribosomal protein genes. The data were compared with the corresponding genes/operons from Bacillus subtilis, Escherichia coli, Mycoplasma capricolum and Mycoplasma gallisepticum.