In the present paper, we pointed out several problems in the classification of anuran trypanosomes. We also reported the result of the blood survey of the frogs carried out in Western Japan in 1990, 1992 and 1996. The following frogs were infected with the trypanosomes : Hyla japonica (Trvpanosoma nagasakiense) ; Rana nigromaculata (T. rotatorium type, T. loricatum type and T. miyagii type) ; R. rugosa (T. chattoni type and T. rugosae) ; R. limnocharis (T. rotatorium type and T. tsunezomiyatai) ; Rhacophorus schlegelii (T. rotatorium type and T. oitaense). The detection rate of the trypanosomes was very low compared with the data obtained in 1978 in Nagasaki area, western Kyushu (Rana nigromaculata : 3 trypanosome positive cases in 10 frogs ; R. limnocharis : 6 in 7 ; R. rugosa : 2 in 4).