Abstract: Abstract: ‘Nanfeng’ tangerine (Citrus reticulata), favorite for its sweet-fleshed and thin-rind fruit, is one of the oldest citrus cultivars in China. However, the decline of its fruit quality affected its commodity value. In order to explore a rapid and effective breeding programme for cultivar improvement, we performed Agrobacterium-mediated transformation of this cultivar using embryogenic callus induced from hypocotyl of seedling. Ti plasmid pROKII with the Arabidopsis APETALA1 (AP1) gene and a neomycin phosphotransferase II (NPTII) gene was used in this experiment. Totally, twenty-two resistant callus clusters were obtained with a mean number of 7.3 cell lines per plate. Further PCR and Southern blot analysis confirmed that transgenes were integrated into citrus genome. Though we have not succeeded in regenerating whole transgenic plants, this study indicate that embryogenic callus of ‘Nanfeng’ tangerine is ideal explants for genetic engineering.