Ultisols are one of the dominant soil orders in Indonesia, accounting for approximately 25% of the total land area. The main problem of this soil is high aluminum (Al) saturation with low pH and plant nutrients. The study was intended to determine the effect of liquid organic fertilizer (LOF) from household waste on the availability of N, P, K, and mustard yield in Ultisols. The research used a complete randomized design (CRD) with six concentrations of liquid organic fertilizer of household waste. The treatments were repeated four times. The treatment included control, 10, 20, 30,40, and 50 ml LOF in a liter of water. The study revealed that the liquid organic fertilizer from household waste increased 1.06 folds of total soil N and 1.04 folds of exchangeable-K compared to the control but did not affect available P. Also, soil pH was comparable among treatments. The greatest concentration of LOF (50 ml per liter of water) exhibited the highest yield of mustard, indicated by the highest fresh and dry shoot weight. In general, the study contributes to the development of eco-frindly agriculture.