Competition ELISA test using sparganum specific monoclonal antibodies (Mab) was investigated to improve the diagnostic specificity of sparganosis. By cell fusion, one hybridoma clone secreting anti-sparganum specific Mab was selected (Sp-20), which reacted on bands of 32 kDa and 38 kDa. Sp-20 reacted on calcium corpuscles on IFA. By micro-ELISA, 16 of 17 sparganosis cases (95%) were found positive, but 1 of 18 clonorchiasis cases (5%), 4 of 16 cysticercosis cases (25%) and 2 of 16 normal controls (11%) showed false positive reactions. On the other hand, by competition ELISA using a sparganum specific Mab (Sp-20), 16 out of 17 (95%) of sparganosis cases were found positive, but 2 of 18 clonorchiasis cases (10%), 2 of 16 cysticercosis cases (12%), 3 of 16 paragonimiasis cases (18%) and 1 of 16 normal controls (6%) showed false positive reactions.