Abstract: This experiment was carried out at Khon Kaen University, Thailand to investigate the effects of nitrogen and potassium chemical fertilisers upon growth, chemical components and seed yield. Urea and potassium chloride were used for nitrogen and potassium sources, respectively. Nitrogen application rates were 0, 62.5, 125 and 187.5 kg N/ha and potassium rates were 0, 50, 100 and 150 kg K2O/ha. The experiment was laid in a 4 x 4 factorial arranged in a Randomized Complete Block Design (RCBD) with four replications. The plant samples were taken at 52 and 82 days after emergence for dry weights of stem, leaves, flower heads, and leaf areas, and 93 days after emergence for seed head dry weights, seed yields and 1000-seed weights. The results showed that leaf dry weights and leaf areas of the sorghum plants at 52 days after emergence increased with an increase in nitrogen levels whilst potassium levels had no significant effect. At 82 days after emergence, total dry weights, stem dry weights, leaf dry weights, flower head dry weights and leaf areas were unaffected by both nitrogen and potassium levels. This was also true for Neutral Detergent Fibre (NDF), Acid Detergent Fibre (ADF) and Dry Matter Degradability (DMD). Crude Protein (CP) values increased with an increase in nitrogen levels while a reverse was found with the brix values for both nitrogen and potassium levels. At 93 days after emergence, seed head dry weights, seed yields and 1000-seed weights were unaffected by both nitrogen and potassium levels.