The indirect immunofluorescence antibody test was performed on serial blood samples from 8 young New Zealand White rabbits with experimental encephalitozoonosis. The test showed seroconversion in 6 of the 8 infected rabbits by the 8th day after inoculation and in all rabbits by the 15th day. Antibody titers reached a peak by about the 36th day after inoculation and remained significantly elevated until the termination of the experiment at 84 days after inoculation. None of 4 sham-inoculated rabbits showed an immunofluorescence response by the 60th day after inoculation. Immunofluorescence and intradermal test responses were compared before infection and at the 60th day after inoculation in a total of 32 experimentally infected rabbits. Both tests were equally effective (100%) in detecting infected animals. Six of 8 (1st group) and 22 of 24 (2nd group) experimentally infected rabbits were confirmed histologically to have lesions compatible with encephalitozoonosis. No cross reactions were observed between Encephalitozoon cuniculi and Toxoplasma gondii, Eimeria perforans or E. stiedai by intradermal test or immunofluorescence test.