To study the effect of corm density on yield and qualitative traits of saffron (Crocus sativus L.) under different biological and chemical nitrogen fertilizers, a factorial experiment based on completely randomized block design with 3 replications was done in 2014 at Shahr-e-Rey region (Ghomi Abad). The experimental factors were: corm density in 3 levels (60, 120 and 180 corm per square meter) and biological and chemical nitrogen fertilizers in 4 levels (without fertilizer application, 150 kg.ha-1 of Urea, 5 L.ha-1 of Nitroxin and 75 kg.ha-1 of Urea +5 L.ha-1 of Nitroxin). The results indicated that the corm density affects number of daughter corm, fresh daughter corm weight, corm diameter, dry stigma and style weight, dry and fresh flower weight significantly. Mean comparisons also indicated that by increasing corm density from 6o to 180, saffron dry yield of saffron improved by 2.7 fold. However, increasing corm density reduced corm diameter, fresh corm daughter weight and their numbers per square meter. It can be concluded that nitroxin as an organic fertilizer, increases vegetative traits and saffron dry yield (stigma + style weight) to 2.08 kg.ha-1 and highly improves in qualitative traits like Safranal, Picrocrocin, and Crocin. It can be also said that combined use of nitroxin and urea would be an alternative method to reduce application of urea.