Pekasam is a traditional fermented fish dish from West Kalimantan, prepared using salt and cooked rice. However, the optimal concentration of cooked rice for making pekasam is unknown. This study aims to determine the effect of variations in cooked rice concentration on physicochemical properties, organoleptic characteristics and nutritional composition of Nila or Tilapia (Oreochromis niloticus) pekasam. The study used a Completely Randomized Design (CRD) with three cooked rice concentration treatments, namely 40%, 70% and 100% of the fish weight. A 1 kg Nila, covered with salt and cooked rice, was fermented in an airtight glass jar for 7 days. Physicochemical, organoleptic, and proximate tests were conducted at the Tanjungpura University Laboratory. Organoleptic testing involved 30 untrained panelists using a line scale. Data were analyzed using ANOVA. The results showed that pekasam with a 70% cooked rice concentration had a brighter color (L = 26.84), higher water content (57.83%), and the highest salt content (23.00%) and pH (5.79). Pekasam with a 70% cooked rice also had a distinctive aroma, attractive color, medium chewy texture, and a balanced tart and salty taste. Proximate tests showed that pekasam with a 70% cooked rice concentration had the highest protein (9.527%), carbohydrates (18.358%) and calorific (138.378 Cal.g-1) content. The 70% cooked rice concentration produced pekasam with an optimal physicochemical, organoleptic and nutritional quality.