The prevalence of blood parasites was investigated in 701 Japanese wild birds for 13 years from January, 1988 to March, 2001. Most of the injured or sick birds were caught in the suburbs of Kobe City, Hyogo Prefecture and brought to the zoo for clinical care. Among all the birds examined, 10.6% were infected with hematozoa belonging to three genera as Plasmodium (1.7% of the samples), Haemoproteus (5.1% of the samples) and Leucocytozoon (4.6% of the samples), and two birds (0.29% of the samples), a Japanese grosbeak (Coccothraustes personatus) and a dusky thrush (Turdus naumanni), were infected with microfilariae. Mixed infection with Leucocytozoon sp. and Haemoproteus sp. was observed in 6 individuals of 4 species and that with Leucocytozoon sp. and microfilariae was observed in 2 individuals of 2 species of bird. Relatively high positive rates were 75%(3/4) in the scops owl (Otus scops), 71.4% (10/14) in the ural owl (Strix uralensis), 57.7% (15/26) in the jungle crow (Corvus macrorhynchos), 57.1% (4/7) in the black-tailed gull (Larus crassirostris), 55.6% (5/9) in the brown hawk owl (Ninox scutulata), 41% (16/39) in the carrion crow (Corvus corone) and 24.1% (7/29) in the night heron (Nycticorax nicticorax).