Kepel is a characteristic plant of Yogyakarta that has many benefits for traditional medicine. The existence of kepel is limited, so conservation needs to be done for save genetic material or DNA. DNA can be obtained from the process of DNA isolation. The success of DNA isolation can be seen from the results of high quality and quantity, by optimizing DNA isolation techniques. This study was aimed to determine the sample weight and incubation time to produce the best quality and quantity of DNA. The method used was an experiment compiled in a single randomized complete design (CRD) consisting of 9 treatments with 3 replications, so that 27 units were obtained. The treatments used in this study were sample weight 0.1g, 0.2g, 0.3g and incubation time 15, 30 and 45 minutes. The result of research was sample of weight 0,2 gram and incubation time 30 minutes might be the best samples to produce highest yield of DNA