Soybean production has not been able to meet market demand which has caused the fulfillment of soybeans to be imported. Most imported soybeans come from Monsanto, America. One gene for making transgenic plants is the EPSPSCP4 gene. Meanwhile, GMO or GMO products from Indonesia have not been labeled on packaging products, so that consumer rights have not been fulfilled. The aims of this research were to obtain product requirements from DNA isolation and EPSPS-CP4 gene conversion by PCR (Polymerase Chain Reaction) method on soybean plants (Glycine max) from the Main Market of the Daerah Istimewa Yogyakarta. The Main Market discussed are Sentral, Beringharjo, Prawirotaman and Gamping markets. The research method used is a method of observation conducted in the laboratory by taking samples using purposive sampling. In this research, the quantification of DNA isolation products with various values ranged from 1.00 - 3.00 on A260 / 280 and A230 / 260 with concentrations ranging from 200 ng / μl - 400 ng / μl. From sample DNA amplification, 9 samples from 10 samples tested showed that the EPSPS-CP4 gene was detected and 1 DNA band did not appear. Soybeans detected by EPSPS-CP4 genes were American No 1 and 2 soybeans, American soybeans, No Name 1 and 2 soybeans, Galunggung soybeans, Wonosari soybeans and Anjasmoro soybeans.