Serological techniques were used to study Orphulella punctata (De Geer) predators. For preparation of antiserum, rabbits were immunized by the limphonodule injection method with antigens obtained from O. punctata male. Serological tests were performed using double diffusion in agar gel. Specific serological reactions were obtained 13 days after the 1st inoculation. After the 2nd inoculation 5 precipitation lines were observed. In the reactions with female antigens there were 2-4 lines, while egg antigens showed 2 lines. These variations in the number of lines were attributed to different physiological states and to ontogeny. Positive reactions were observed for spiders and chrysopids captured in the field.