Dot-immunobinding technique was used to detect circulating Toxoplasma antigens in the sera of men and animals. Serum samples were collected from mice and rabbits infected experimentally with parasites of the RH strain of T. gondii while human sera were obtained from persons suspected of having active toxoplasmosis. Circulating Toxoplasma antigens were detected in the samples of mice sera that had been collected since the 2-nd day of iniection and in the sera of rabbits during 2 and 3 week of iniection. From amongst 146 human sera, 35 (24%) gave positive reaction in the test while 14 (9,5%) produced doubtful results. The experiments proved the method to be sensitive, reproducible and easy to perform. It obviates the need of special equipment while most of the necessary reagents are commercially available. High percentage of doubtful results is the main drawback of the method.