A study was carried out to determine whether thiamine deficiency in northeast Thailand is linked with parasitic infection. We assessed the thiamine status and tested for parasitic infections in 231 children between 6 and 12 years of age in Nam Phong District of Khon Kaen Province, Thailand. Thiamine deficiency [thiamine pyrophosphate effect (TPPE) > 20%] and parasitic infections (mostly Strongyloides stercoralis) were identified in 16 and 45% of the children, respectively. No association between thiamine deficiency and parasitic infection was found. The general health of the children, according to Thai standard anthropometric curves, was within the normal range. The suboptimal thiamine status and the high prevalence of parasitic infection require attention.