Blastocystis hominis is a pathogenic protozoon that lives in the human bowel and causes diarrhea: the mode of transmission is a passive one, through the ingestion of stool-contaminated water or foods that contain infective forms of the parasite. The purpose of this study is to report the prevalence of Blastocystis hominis among food vendors in the markets within the Xochimilco jurisdiction, Mexico City, Mexico. A cross-sectional study was conducted in which food vendors answered an epidemiological questionnaire and underwent a serial stool culture. The frequency of the intestinal parasitoses reported was estimated and an analysis was carried out associating the presence of Blastocystis hominis with socio-economic and hygienic factors using the odds ratio at a 95% confidence interval. The frequency of intestinal parasites and commensals was 50.4%; Blastocystis hominis was found in 48 (41.7%) food vendors. The risk analysis showed that Blastocystis hominis was associated with: male gender, poor personal hygiene habits, personal history of parasitosis, and family history of parasitosis. The prevalence reported is high when compared with other populations studied. The relevance of this report lies on the fact that food vendors handle foods and could transmit the infection to consumers.