A number of higher plant protein Ser/Thr phosphatase (PP) genes have been recently identified encoding PP1, PP2A, PPX and PP7. Using polymerase chain reaction on Physcomitrella patens (Hedw.) B.S.G. (Funariales) genomic and cDNA, we have analysed the protein Ser/Thr phosphatase composition in this lower plant. The analysis revealed the presence of PP1 (4 isoforms), PP2A (4 isoforms), PPX (1 isoform), PP5 (I isoform) and putative PP7-related phosphatases (3 isoforms). In addition, we identified a cDNA fragment homologous to <<expressed sequence tags>> from Arabidopsis thaliana and Oryza sativa, which probably encode as yet unidentified phosphatases distantly related to the PPP family. These results provide first structural data about the protein Ser/Thr phosphatases in lower land plants.