the aim of this research was to determine the effect of physical, chemical and physiological of several maturity stages of rambutan cultivar simacan in Wonosaro, Gunung Kidul, Yogyakarta. this research was conducted from march to may 2004 used a single factorial randomized complete design (RCD), consisted of six levels, i.e: A ( rambutan with red stages of maturity), B (rambutan with yellowness red stages maturity ) C (rambutan with yellow stages of maturity ), D ( rambutan with greenness yellow stages of maturity) , and E (Rambutan with green stages of maturity). the treatment was done in three replications. based on the research, it is better for farmers to harvest rambutan simacan once they are in red stage. in this stage the rambutan will have its sugar content and vitamin C content in its higher.