A preliminary study of anti-phenolic glycolipid-I (PGL-I) IgM antibody detection using M. leprae gelatin particle agglutination (MLPA) test kit is described. Antibodies were demonstrated in 70% of our leprosy patients taking antileprosy treatment. The percentage of positivity of multibacillary cases was 86.0, whereas that of paucibacillary cases was 30.0. Good correlation was found between bacteriological index and the presence of antibodies. Antibodies were detected in 28% of our patients released from treatment. Fourteen out of 27 household contacts were found to have antibodies but none of the normal controls were seropositive. These preliminary data demonstrate that MLPA test is not applicable as sero-diagnostic test or as a test of cure, but may be useful for epidemiological studies and as a research tool.