This study was aimed to evaluate the reproduction index of Kacang goat does reared under closed population with extensive farming system in the Fishpond area of Buduran Sub-District, Sidoarjo Regency, East Java Province, Indonesia. A total of 146 Kacang does data were purposively selected and collected from around 1, 700 Kacang goat population through survey and interview with 12 farmers. All of the obtained data collected, were analyzed descriptively. The results showed that most of the Kacang goat dams (67.80%) delivered single kid, and then followed with twin (30.13%) and triplet (2.05%) per partus, with the average litter size of 1.34 ± 0.51. The pre-weaning mortality observed was about 20.40%. The kidding interval and days open were 7.41 ± 0.99 and 2.41 ± 0.99 months, respectively. Moreover, the results also showed that the Kacang does had the reproduction index of 1.69. The research concluded that Kacang goats are well adapted and suitable to be reared with extensive farming system in Sidoarjo Regency regarding to reproduction index and -performances.