To investigate the influence of fertilizer levels on onion seed production and quality, an experiment was carried out at Caçador, located in the highlands of Santa Catarina, on a brown organic distrofic lactosoil, in 1984/85. Fertilizer levels were evaluated in a randomized complete block design, with various levels of NPK. The results of this research indicated that no effect was observed on the number of flower stem and on quality and production of onion seeds. On the other hand, K showed slightly positive effect on the seed production.