This study examines the nutrient availability and soil fertility status in Raja Uncak rice fields, a traditional farming system in Kapuas Hulu Regency, West Kalimantan, Indonesia. Soil samples were collected from 6 Raja Uncak fields and analyzed for physical and chemical properties. Results indicate that Raja Uncak soils are predominantly acidic (pH 4.42 - 4.83) with high – very high organic matter content (3.94% and 11.33%). Base saturatin were found to be limiting factors, while potassium (K) levels were generally adequate. The study provides insights into the unique soil characteristics of Raja Uncak systems and suggests potential strategies for sustainable soil management in these traditional agroecosystems.