Aims: This study was conducted to measure the efficacy of the marine antagonist Rhodosporidium paludigenum in the suppression of postharvest decay of Chinese winter jujube caused by Alternaria alternata and to explore the possible mode of action involved. Methods and Results: The efficacy of controlling postharvest diseases by R. paludigenum was examined. Rapid yeast colonization of wounds was observed during the first 48 h at 25 degrees C. The yeast at 1 x 108 cells ml-1 of washed cells suspension provided better control of A. alternata than any other treatment. The concentration of the antagonist had significant effects on biocontrol effectiveness: as the concentration of R. paludigenum was increased, the disease incidence decreased. Meanwhile, R. paludigenum significantly inhibited the natural development of decay and did not damage fruit quality parameters including lightness values, hue angle, firmness, soluble solids, ascorbic acid and titratable acidity in 21 days' storage at 25 degrees C. Conclusions: Rhodosporidium paludigenum was effective in controlling postharvest decay of Chinese winter jujube and did not impair fruit quality parameters. Significance and Impact of the Study: Rhodosporidium paludigenum can be used as a nonchemical agent in postharvest biological control of Chinese winter jujube.