Aedes albopictus is a mosquito widely distributed across tropical and sub-tropical regions of the world and is associated with the transmission of several arboviruses including that for Dengue fever, Yellow fever and Chikungunya. Ae. albopictus is increasingly relevant to public health due its ability to successfully colonize both urban and rural habitats, favouring the wide dispersion of viral infections. Trypsin-like enzymes play an important role in the Aedes albopictus digestive process. The trypsin-like enzymes present in adult mosquito were characterized previously, but little is known about enzymes in the larvae. In the present work, for the first time, from the gut of fourth instar larvae of Ae. albopictus, a protease was purified by affinity chromatography on Soya Bean Trypsin Inhibitor covalently linked to Sepharose. On gelatin zymography of the gut extract of fourth instar larvae of Aedes albopictus, there were four major protease bands of which one corresponds to the isolated protease. The isolated protease is a serine protease as it is inhibited by serine protease inhibitors, PMSF and Soya Bean Trypsin Inhibitor, to the extent of 88.3±0.002% and 87.2±0.003% respectively. On SDS-PAGE, the isolated protease runs as a 21.5 kDa single band indicating that it a pure protein. As serine proteases represent the major proteases in the gut of mosquito larvae, targeting the protease isolated from gut of the larvae of Ae. albopictus will be a promising strategy for the control of the mosquitoes.