Strain differences in midgut basal lamina thickness, assessed by measurement in transmission electron micrographs, and disseminated infection rates of dengue-1 virus were compared among three laboratory strains of Aedes albopictus (Skuse). Mean basal lamina thickness for the New Orleans and Houston strains were significantly greater than those for the Oahu strain, which exhibits a higher disseminated infection rate than the former two. Although basal lamina thickness among the F1 progeny of reciprocal crosses of the Oahu and Houston strains were intermediate between the parental strains, they were too variable to be useful as markers in genetic studies. Measurements of basal laminae among individuals of the New Orleans strain, with disseminated or nondisseminated infections, failed to demonstrate a role for basal lamina thickness as a modulator of dengue-1 virus dissemination across the midgut epithelium of Ae. albopictus.