The practicability of four diagnostic methods for entamoebiasis histolytica including micro-gel diffusion precipitin test (MGDP), indirect immunofluorescent antibody test (IFA), indirect hemagglutination test (IHA) and enzyme-linked immunosorbent assay (ELISA) was evaluated. The serological test methods were compared by using sera obtained from 30 entamoebiasis histolytica patients and 130 normal health individuals. The highest sensitivity was obtained with the method of ELISA, followed by IFA and IHA : the lowest was obtained with MGDP. On the contrary, the high specificity was obtained with IHA, IFA, MGDP : the lowest was obtained with ELISA. Intensity of the antibody titers in IHA was correlated well with that of IFA. In addition, we studied antibodies nonspecifically reactive to Entamoeba histolytica in sera from E. histolytica-negative individuals with high CRP patients with regard to the sensitivity and specificity. Among 101 sera examined, six showed false positive results of which five were the sera with extremely high CRP.