beta-Galactosidases have a wide application in the food and pharmaceutical industries. Recently, beta-galactosidase was also found to participate in agar degradation. In this study, the second reported agarolytic beta-galactosidase was found in the marine bacterium Agarivorans gilvus WH0801 and characterized. The beta-galactosidase named AgWH2A (83 kDa) exhibited good activities under optimal hydrolysis conditions of pH 8.0 and 40 A degrees C. AgWH2A could cleave the first D-galactose of agarooligosaccharides from its nonreducing end to produce neoagarooligosaccharides, but could not act on the neoagarooligosaccharides. AgWH2A has great potential in the comprehensive utilization of marine red algae.