Yeasts and molds in 25 retail food samples were enumerated by plating with antibiotic potato-dextrose agar adjusted to pH values in the range of 2 to 10. In general, counts for a given sample were similar in the pH range of 4 to 7; however, most samples showed maximum counts at pH 8. The effectiveness of antibiotics used to suppress bacteria diminished at pH 8 and above, which may account for some of the high counts obtained. Consequently, for routine laboratory analysis, adjustment of the medium to pH 5 to 6 is recommended.