The effects of breeding habitat characteristics on the larval density of Anopheles minimus Theobald were studied in a perennial stream in the foothills of Chiang Mai province, northern Thailand. Data on 41 different variables related to plant cover and stream physical attributes in 200 sections, each 10 m long, were collected along with larval data during the dry and wet seasons of 1998 and 1999. Larval density was significantly higher in the dry season than in the wet season. In the dry season, An. minimus density was negatively correlated with water current velocity, height of aquatic large-leaved plants, and height of riparian small-leaved plants; and positively correlated with the cover of riparian ferns. The dry season prediction model, which explained 51% of the variation of An. minimus, was as follows: y_min = 0.1980–0.1733*water velocity – 0.0317*height of aquatic large-leaved plants – 0.0249*height of riparian small-leaved plants 0.0192*cover of riparian ferns – 0.0170*height of stream banks. The influence of vegetation characteristics on larval density may not be as large as previously assumed. We conclude that factors other than those measured here may account for a large part of the variation in larval density.