The reseach was conducted to determine the effect of Liquid organic fertilizer of goat milk processing wastes with various treetment and the best treetment on the growth and yield of lettuce plants. The study was carried out from July 2017 through September 2017 at the Greenhouse and soil Laboratory of Faculity of Agriculture, Universitas Muhammadiyah Yogyakarta. This reseach was designed using single faktory experiment method arranged in CRD ( Completely Randomized Design )and the process of making LOF (liquid organic fertilizer) based on goat milk processing waste combined with urea fertilizer as a comparison, there are 5 treatments of Nitrogen balance : P1 = (100% N- Urea) + ( 0 % N-LOF Goat milk processing wastes); P2 = (75% N- Urea) + ( 25% N- LOF Goat milk processing wastes); P3 = ( 50% N- Urea) + (50% N- LOF goat milk processing wastes); P4 = (25% N- Urea) + (75% N- LOF goat milk processing wastes); P5 = (0% N- Urea) + (100% N- LOF goat milk processing wastes). The result showed that the use of liquid organic fertilizer of goat milk processing wastes gives the same effect or no significant difference in the use of Urea fertilizer on lettuce plant with the same N content.