Durum wheat is one of the major cereal crops produced in Adea district of Oromia Regional State, for both home consumption and the market. However, its productivity is low due to the low availability of soil nutrients and agro-climatic variabilities. Therefore, a field experiment was carried out in Debre Zeit agricultural research centre during 2023 main cropping seasons to determine the effect of blended NPSB and N fertilizer rates on the productivity and quality of durum wheat. The treatments consisted of four levels of blended (0, 50, 100, and 150 kg NPSB ha −1 ) and five levels of nitrogen (0, 46, 69, 92, 138, and 184 kg N ha ) fertilizer rates. The experiment was laid out in a randomized complete block design in a factorial arrangement and replicated three times. Data such as agronomic and quality parameters were collected and analyzed using SAS-JMP software. Analysis of the results revealed that chlorophyll content 2, −1 normalized difference vegetation index 1 and 2, days to heading, days to physiological maturity, plant height, grain yield, harvest index, thousand kernel weight, protein content, and hectolitre weight were very highly significantly (p<0.001) affected by the interaction effect of blended NPSB and nitrogen fertilizer rates. The highest values of phenological parameters (days to 50% heading [66.33] and days to physiological maturity [116.33]), growth parameters (chlorophyll content [58.6], normalized difference vegetation index 1 and 2 [0.60 and 0.89, respectively], plant height, total tillers and effective tillers m [95.5, 366.3 and 233.3, respectively]), yield and yield-related parameters (number of kernels per spike, above-ground -2 biomass yield, grain yield, harvest index [47.3, 4.6, 3451 and 76, respectively]) and quality parameters (protein content, hectolitre weight and thousand kernel weight [16.6, 79.3 and 41.3] were recorded at the combined application of 150 kg of blended NPSB with 184 kg of N ha . The result of the economic analysis also showed that the combined application of 150 kg NPSB and 184 kg N ha −1 −1 gave a maximum economic benefit of 198,971ETB ha with an acceptable marginal rate of return (10,395%). Therefore, it could be concluded that the combined application of 150 kg of blended NPSB with 184 kg ha of N fertilizer rates gave the maximum grain yield, protein content, hectolitre weight, and thousand kernel weight yield with the highest net benefit. -1 −1