The sequences of 10 conservative regions (CR) of minicircles of 6 selected isolates of freshwater fish try-panosomes have typical organization of this region with high degree of sequence conservation. The comparison with CRs of other trypanosomatids showed that freshwater fish trypanosomes represent a compact separate group within the genus Trypanosoma. The alignment of all sequences obtained revealed, however, the existence of 2 types of CRs in sequenced minicirclcs, with the differences concentrated in a short region. Taxonomic consequences of these results arc discussed.