Bacillus cereus, bacteria that commonly occur in foods, can potentially cause foodborne illness. Two important factors that contribute to the illness are the number of B. cereus in food and the ability of the organism to produce enterotoxins. This study investigated the number of B. cereus cells in dairy and cereal products in Thailand, using the plate count method and the presence of diarrheal-enterotoxin genes in the isolates through the polymerase chain reaction (PCR). The genes encoding hemolysin BL (hblA, hblC, hblD), nonhemolytic enterotoxin (nheA, nheB, nheC), cytotoxin K (cytK) and enterotoxin FM (entFM) were the targets of the PCR. B. cereus was found in all pasteurized milk samples and in 37.7% of the cereal product samples, ranging from 50 to 1.7 × 103 cfu/g. PCR results revealed that each gene occurred in more than half of the foodborne isolates tested. A large proportion (96%) of the isolates harbored enterotoxin genes and is considered to be potentially diarrhegenic. © 2008, The Author(s).