Porcupines are unique mammals, their upper body is covered with hard hair resembling sharp cylindrical spines and belongs to the order Rodentia. It has long been used as a source of animal protein. Javan porcupine (Hystrix javanica) is an endemic animal on Java and its population is estimated to continue, due to habitat destruction, poaching, and its use without a conservation. Observations on the growth of young javan porcupines were carried out for 12 months in Small Mammal Captivity, Research Center Biology - Indonesian Institute of Sciences. This study aims to determine the growth performance of young porcupines in captivity based on number of births, namely singles, twins, and triplets. The young will be with their mother for 3 months, they will be placed in individual cages. Weighing porcupines is done once a week. The results suggest that porcupines continue grow until they are 12 months old and probably continued. The average weight gain of single born was 30.31 g/day; birth of twins 29.65 g/day, 29.72 g/day; and birth of triplets were 29.57 g/day, 28.14 g/day, and 29.79 g/day. Prediction of 12-month-old porcupine carcass production for single, twins, and triplets, respectively, was 6740.86 g; 6593.15 g; and 6470.50 g.