Recently, application of liquid organic fertilizer (LOF) in organic farming practices is of importance to prevent further soil degradation due to prolong and massive use of synthetic fertilizers. LOF provides faster plant nutrient availability than solid organic fertilizer. However, quality of LOF is substantially dependent on its sources. Animal wastes from rabbit, goat, and cattle are scarcely used as sources of LOF production. The study aimed to determine soil chemical improvement and potassium uptake by mung beans as affected by LOF in Ultisol. The experiment was conducted at the Greenhouse, Faculty of Agriculture, employing Completely Randomized Design with two factors. The first factor was animal wastes, consisting of goat, rabbit, and cattle wastes. The second factor was LOF concentration, consisting of 0%, 25%, 50%, 75%, and 100% LOF. LOF was prepared by mixing altogether animal faeces, urine, soil, green biomass, EM-4 and fresh water to a total volume of 10 l in a plastic container. LOF was decanted to the polybag every week starting at one week after mung beans planting for four weeks to a total volume of 750 ml per polybag. Variables observed included soil pH, total soil organic-C, exchangeable K, soil nitrate-N, K concentration in plant tissue, K-uptake, and shoot dry weight of mung beans. The result showed that application of LOF from rabbit waste had the highest increment of soil pH as compared to the other treatments. However, exchangeable K was observed highest at the treatment of LOF from goat waste. Sources of LOF from animal wastes did not have an effect on K-uptake by mung beans. In addition, application of LOF up to 100% was able to improve soil chemical properties as indicated by the increase in soil pH and exchangeable K. So did the concentration and uptake of K, as well as shoot dry weight. Fertilization with LOF has benefit to the improvement of soil chemical properties leading to better K uptake.