The present study was conducted in Upper Brahmaputra Valley Zone of Assam, India in January, 2020 to study resource use efficiency in Sali rice cultivation in mechanised and non-mechanised farms. A sample of 120 farmers was selected randomly from two Agricultural Development Officer Circle (ADO Circle) each comprising of 5 villages. Results revealed that human labour and seed were used comparatively in lesser quantities in mechanised farms than the non-mechanised farms, while manures and fertilizers were applied in higher quantities in mechanised farms than the non-mechanised farms. Coefficient of fertilizer was significant in both mechanised and non mechanised farms. On the other hand, coefficients of elasticity of seed and machine labour were positively significant in mechanised farms, while FYM was observed to be positively significant in non-mechanised farms. Human labour was found to be negatively significant in non-mechanised farms. In mechanised farms, the ratio of Marginal Value Product (MVP) to Marginal Factor Cost (MFC) was highest for machine labour (1.85) followed by seed (1.59) and fertilizers (1.52). The coefficients of the production function were estimated to be positively significant for seed, fertilizers and machine labour used, while the allocative efficiency ratios revealed that an additional expenditure of one rupee on these inputs would increase the gross returns by ` 1.59, ` 1.52 and ` 1.85 respectively. In case of non-mechanised farms, the ratio of MVP to MFC for area, seed, plant protection chemicals, human labour and bullock labour were found to be less than unity.