We measured the seasonal abundance and bloodfeeding behavior of species A and C of the mosquito Anopheles minimus Theobald 1901 in an endemic malarious area of western Thailand. An. minimus s.l. is a major vector of human malarial and filarial parasites in Southeast Asia. Mosquitos were collected once a month for one year using four collection methods: human-baiting indoors, human-baiting outdoors, human-baiting in the forest, and cow-baiting. We found that both species A and C tend to feed from cows rather than humans; we did not find any preference for indoor, outdoor or forest-biting in either species. Both species had a peak biting density in October/November, at the end of the rainy season, and species C showed a second, smaller peak at the end of the cool season. These findings are discussed in relation to previous reports of the behavior of An. minimus s.l., particularly in light of suggestions that An. minimus s.l. has changed its feeding behavior in response to DDT spraying.