is an important target for vector control because of its ability to transmit pathogens that cause disease. Most populations are resistant to pyrethroids and often to organophosphates, the two most common classes of active ingredients used by public health agencies. A knockdown resistance ( ) mutation, resulting in an amino acid change from a leucine to phenylalanine in the voltage gated sodium channel, is one mechanism contributing to the pyrethroid resistant phenotype. Enzymatic resistance has also been shown to play a very important role. Recent studies have shown strong resistance in populations even when is relatively low, which indicates that factors other than may be larger contributors to resistance. In this study, we examined, on a statewide scale (over 70 populations), the strength of the correlation between resistance in the CDC bottle bioassay and the genotypes and allele frequencies. Spearman correlation analysis showed only moderate (-0.51) or weak (-0.29) correlation between the genotype and permethrin or deltamethrin resistance, respectively. The frequency of the allele was an even weaker correlate than genotype. These results indicate that assessing in populations of is not a good surrogate for phenotypic resistance testing.