The fruit quality parameters of several Japanese plum cultivars (Prunus salicina Lindl) were studied in two experimental orchards under organic and conventional management. The study was performed during 2008-2010 in the province of Seville (SW Spain). Colour, weight, size, firmness, soluble solid concentration and acidity were measured for fruit quality evaluation. Yield was also determined. In general, the organic fruit was of smaller size and weight. There was little difference in the colour of most of the varieties, but some varieties such as 'Friar' and 'Black Amber' were more colourful in the organic orchard. The soluble solid concentration and acidity were similar in the fruit from both orchards. The organic plums showed firmness equal to or slightly greater than conventional ones. Dry matter and nitrites were analysed in 2010, and no significant differences were observed in most of the varieties. The accumulated fruit yield was significantly superior in the conventionally managed orchard.