Bacterioplankton community composition was studied in 12 lakes in three different geographic regions in Scandinavia using denaturing gradient gel electrophoresis (DGGE) and sequencing of 16S rDNA. Area-specific abundant taxa were found in the lakes in two of the regions. In the region of Uppland the lakes had an alpha-proteobacterium, belonging to the subgroup Alpha V in common. The Alpha V bacteria appeared to be favored by neutral or higher pH values. The lakes in Lappland were found to harbor Actinobacteria, which appeared to be favored in bog lakes. No abundant taxon was found to be in common for the lakes in Svalbard, the third region studied.