Abstract <p>Saffron is one of the most expensive spices in the world with high medicinal value. Therefore, it is necessary to try to reduce the effects of factors limiting its growth and increase the yield of this product. Iran, with its diverse climate and fertile soil, plays an important role in global agricultural production, including saffron. This study was conducted in GilaneGharb County is in Kermanshah province in order to investigate nitrogen (N) and humic acid (HA) on some quantitative and qualitative characteristics of saffron plants. It was conducted as a factorial experiment in a randomized complete block design with three replications in the 2023–2024 crop year. The first factor includes four levels of N (0, 50, 75 and 100 kg/ha urea) and the second factor includes three levels of HA (0, 100 and 200 mg/L). Nitrogen was applied in two stages (March 1 and 15, 2024) and humic acid was applied as a foliar spray (March 1, 2024). According to the results obtained, different levels of N and HA had a significant effect on the growth and yield features of saffron plants, and with increasing N and HA levels, number of leaves (24.00), corms (9.29), length of stigma (3.25 cm), and dry weight of stigma (0.084 g) increased. Simultaneous application of N and HA increased the dry yield of stigma (4.21 g/m²) and crocin (283.33%) and picrocrocin (85.68%). It can be said that the simultaneous application of N (100 kg/ha) and humic acid (200 mg/L) treatments improved the yield and secondary metabolites of saffron, and given the effective role of these fertilizers in yield and improving soil properties in the direction of sustainable agriculture and reducing environmental pollution, they can be recommended.</p>