Grafted plantlets of guava were planted at a density of 4444, 5000, 6666 and 10000 plants ha-1 to standardize the optimum population density and nutrient level for nutritional quality of guava under subtropical conditions of northeast India. The experiment was set up at the AAU–Horticulture Research Station, Assam, India with two factors comprising four planting densities and three nutrient levels, and twelve treatment combinations with three replications were imposed on newly planted guava plants. The plants accommodated at lower densities produce superior quality fruits in respect of all chemical constituents throughout both seasons. The fruits of the plant at density 4444 plants ha-1 in winter and 5000 plants ha-1 in rainy season were found to contain the highest amount of TSS (11.63 & 10.73ºB), reducing sugar (4.66 & 4.46%), total sugar (8.27 & 7.85%), ascorbic acid (202.75 & 196.47 mg/100 g) and pectin (1.17% & 1.08%) respectively in the first year and the trend was reversed in the second year and plants under the highest density (10000 plants ha-1) yielded fruits with lowest qualitative traits irrespective of season and year. The nutrient level also had a significant influence on the quality attributes of fruit, an increased trend was observed with increasing level, and the highest nutrient level (70:45:35g NPK plant-1 for the first year and 130:75:65g NPK plant-1 for the second year) demonstrated significant superiority. The winter season crop was superior to rainy season in terms of chemical characteristics of fruit during both years of investigation.