The salivary gland proteins of adult female Anopheles darlingi were fractionated by reverse-phase HPLC and the five major peaks were submitted for amino-terminal sequencing using automated Edman degradation. The amino acid sequence of one of the purified salivary gland proteins showed similarity with the D7r3 protein of An. gambiae. Cloning and sequencing of two cDNAs allowed the prediction of the complete sequence of the An. darlingi D7 protein. The D7r3 protein is present specifically in adult female salivary glands of An. darlingi and despite being one of the major salivary gland proteins its function is not known. Predictions of secondary and tertiary structures revealed the similarity of the An. darlingi D7 protein to insect odorant binding proteins. This suggests that D7 proteins may act as carriers of hydrophobic molecules in mosquito saliva.