Abstract ntestinal parasitic infections remain a serious public-health problem in Thailand. Most infections result from fecal-oral transmission by ingestion of contaminated water and food, the major vehicles for transmitting infection. This study examined the prevalence of intestinal parasitic infections in 435 stool samples (villagers living in Ban Nong Um = 177, villagers living in Ban Khawao Yai = 98, and teachers living in Amphoe Mueang = 160) in Mahasarakham Province, by formalin-ether concentration technique. The overall prevalence of intestinal parasitic infections in the 435 stool samples was 14.71% (64/435). The highest prevalence was found among villagers living in Ban Khawao Yai with an infection rate of 30.60%, compared with 12.99% and 6.88% among villagers living in Ban Nong Um and teachers in Amphoe Mueang, respectively. Strongyloides stercoralis infection (6.44%) was the most frequent pathogenic intestinal parasitic infection, followed by Opisthorchis viverrini (5.74%) and Taenia sp (1.61%), respectively. Moreover, the prevalence of intestinal parasitic infections in Ban Nong Um and Ban Khawao Yai was significantly higher than among teachers (19.27% vs 6.88%, p < 0.001). In conclusion, instruction in personnel hygiene and appropriate health education on the prevention of parasitic infections should be provided to the population, to reduce parasitic infections in the study area.