Cellulose triacetate membrane filters applied directly to the surface of non-selective blood agar plates were found to be as effective as the use of antibiotic media in isolating Campylobacter jejuni from patients with diarrhea. This method was used in parallel with selective media in the examination of 1000 specimens of feces. Campylobacters were isolated from 56 specimens using all methods. The membrane filter method detected 50 (89%), 45 of which were C. jejuni, and selective media 45 strains of C. jejuni (80%). Membrane filters used in this way can result in the detection of most cases of campylobacter enteric infection and can be used by small laboratories with limited access to selective media. They may also facilitate the isolation of antibiotic sensitive campylobacters.