This study aimed to determine the growth of leaves and roots in the pakcoymustard (Brassica rapa) using hydroponic system with the AB Mix nutrition fertilizer. The data analysis used was to measure the number of leaves (Jd), leaf width (Ld), leaf length (Pd), number of roots (Ba), root length (Pa), and plant weight (Bt). Plant tools and media used were pipes, net pots, panel cloth, rockwool, TDS/EC, and water. The results of the analysis showed that the treatment of AB Mix nutrition gave a significant effect on the meter observing the number of leaves, leaf width, leaf length, number of roots, and root length. At the age of one week the number of leaves consists of three, leaf width: 0.5 cm, leaf length: 1.5 cm, there are 3 roots with the root length: 1 cm. At the age of two weeks, the number of leaves consists of 6, wide: 2 cm, long: 5 cm, there are 5 roots with the long: 3.5 cm. At the age of three weeks the number of leaves consists of 9 leaves, wide: 4 cm, long: 8 cm, there are 9 roots with the long root: 7.5 cm. At the age of four weeks the number of leaves consists of 11 leaves, leaf width: 8 cm, leaf length: 12 cm, there are 13 roots with the root length is 12 cm and a weight plant is 100 gram/plants to use AB Mix nutrients. It is showed that the growth and development of mustard pakcoy (Brassica rapa) hydroponic system with AB Mix nutrition has a significant effect on the growth of leaf number (Jd), leaf width (Ld), leaf length (Pd), number of roots (Ba), root length (Pa) and plant weight (Bt).