Campylobacterjejuni is an enteric pathogen recognized worldwide as a cause of diarrhea. Its isolation from stoQl samples requires a microaerophilic environment that heretofore has been expensive and cumbersome to create. An economical, portable, and simple method is described which involves the production of appropriate concentrations of oxygen and carbon dioxide. Inside a plastic bag are placed two cups, one containing fine steel wool (grade 0) previously soaked in a 2.5% aqueous solution of copper sulfate and the other containing an Alka-Seltzer tablet in tap water. As suggested by Jurgensen et al. (Rev. Bras. Pat. Clin. 18:58-63, 1982), we used the effervescent antacid to generate CO2. By plate counts, we found this method to be as reliable in the cultivation of 20 isolates of C. jejuni in pure and mixed fecal culture as the reference gas method (85% N2, 10% C02, and 5% 02). Analyses of the gas mixture inside the bag after up to 24 h of incubation confirmed the creation of an * Corresponding author.