For the serologic diagnosis of amebiasis in man, the indirect immunofluorescence test (IFT) was used in a study of 3,607 sera, 1,217 of which were used to check specificity. In cases of hepatic amebiasis the IFT was constantly and intensely positive, and therefore has a very high diagnostic value. It can also be used to assess the effect of therapy, but only several months after treatment has begun. However, the IFT cannot be relied on for the diagnosis of amebic dysentery, since in such cases its only advantage is the elimination of the possibility of hepatic complications. It cannot be used to distinguish between chronic amebiasis and post-amebic colitis, or to detect asymptomatic cyst passers. Like other serologic methods, the IFT therefore has precisely defined limitations in the diagnosis of amebiasis. Its principal advantages are that it is easy to carry out and has a high level of reproducibility.