Abstract: The investigation was conducted in 1997 and 1998 at Ege University, Faculty of Agriculture, Department of Horticulture to determine some important fruit quality characteristics of "Marsh seedless" grapefruit cultivar in Izmir (Turkey). Fruits harvested from young and old trees at two different dates (end of November and mid of December) were analyzed in terms of quality characteristics. The average fruit weight ranged between 351 and 385 g, fruit juice content was between 36.9 percent and 43.1 percent, the total soluble solids content of fruit juice was between 9.5 percent and 12.6 percent, total titratable acidity as citric acid was 1.40 and 1.69 g/ml and pH value was between 2.89 and 3.12. It was determined that there were More significant differences between old and young trees in terms of fruit quality characteristics than between two different harvest dates statistically. There were no statistical differences between 1997 and 1996 years in respect to quality.