Quality characteristics of Satsuma mandarin (Citrus unshiu Marc. var. okitsu) harvested in early December according to production areas and sea level altitude of Cheju were investigated. Soluble solids and flesh ratio were 9.06∼12.98, 77.32∼81.27% on citrus fruits harvested in orchards located below 100 m sea level (lower area), and were 10.16∼12.26, 75.00∼81.55% in orchards 150 m sea level altitude (higher area), respectively. Acid content of citrus juice was 0.83∼1.21% in fruits harvested in lower area, and was 0.94∼1.34% in higher area except Hankyung-myun area. The differences of soluble solids and acid contents by harvesting periods for 10 days were 0.91 and 0.82 for soluble solids; 0.15 and 0.13% for acid contents, respectively. In proportion to late harvesting, Brix/acid ratio and fruit quality were improving. Soluble solids of fruits harvested from lower area were higher than those of fruits from higher area, but acid contents were lower in fruits from lower area than in fruits from higher area. In sensory evaluation on fruit appearence, the differences between two altitudes were not clear, but panelists marked higher points on fruits harvested in main production areas, Seogwipo-si and Namwon-cup which are southern areas. Fruit quality harvested in Seogwipo-si areas showed better quality than fruits from other harvested areas.