The objective of this study is to describe some qualities of mangosteen fruit during maturation. Six maturity stages from stage 1 to stage 6, defined by the extension of red or purple colouration on the pericarp were analysed. Changes of external skin colour were recorded using the Commission Internationale de I' Eclairage (L*, a* and b*) colour space coordinates. In the skin,b - carotene, anthocyanin and reducing sugar were measured. The L* and b* value of the skin decreased gradually from stage 1 to stage 6, while a* value increased from stage 1 to stage 3 and remained constant until stage 4 gradually decreased until the fully ripe stage (stage 6). b - carotene increased during the early stage of maturity and gradually decreased until the fully ripe stage, while total anthocyanin and reducing sugar content increased continuously during maturation and reaching a maximum value at fully ripe stage. A close correlation was obtained between anthocyanin and reducing sugar (r = 0.951). In the aril, soluble solids were found to increase from stage 1 to stage 6, while titratable acidity increased at the early stage (stage 1 to 3) and continued to decrease until stage 6.