Abstract. Soetedjo INP, Jansari EA, Ndiwa ASS. 2020. The effect of various dosages of fishbone flour and tofu slurry on chemical characteristics of alfisol and yield of leaf cabbage (Brassica oleracea var. acephala). Trop Drylands 4: 58-62. Alfisol is a type of soil that has been going through intensive weathering and development, which resulted in leaching of nutrients such as N, P, and K. These conditions might be improved by application of organic matters such as various kinds of waste. Fishbone flour and tofu slurry are potential organic waste which might be applied to improve chemical characteristic of alfisol. Factorial research was conducted from January to October 2018. The research was laid out in a Randomized Complete Block Design (RCBD) with 3 replications. The research treatments were og two factors, i.e., kinds of organic waste (fishbone flour and tofu slurry) and various dosage applications (300 g polybag-1, 400 g polybag-1, 500 g polybag-1). Observed data were subjected to Analysis of Variance (ANOVA) followed by a Duncan Multiple Range Test (DMRT) at 5%level. Observed variables included soil nutrient’s content (Total nitrogen, available phospurous, exchangeable potassium) and yield of leaf cabbage (kalian or kale) (Brassica oleracea var. acephala). Result of the research showed that there was no significant effect of either interaction of the two factors or the single factor treatment of organic waste on all observed data. However, dosage of organic waste applications significantly affected nutrients content of alfisol that 500 g polybag-1 produced a higher content of N, P, and K compared to other treatments. Similarly, application 500 g polybag-1 of organic waste resulted in a higher fresh weight of leaf cabbage of 218.83 g polybag-1.