In order to study the effect of different densities of planting on yield, yield components and morphological characters of Fennel, an experiment was carried out in Karaj College of agriculture at 2008. Experiment was conducted based on completely randomized block design with three replications and five plant densities. Five plants spaces were 10, 15, 20, 25, and 30cm. Results indicated that the effect of plant density was not significant on the plant height, seed length and thousand seed weight. However, the effect of plant density on yield, number of umbel per plant and number of main branches was significant in 1% level. Maximum yield (2/431kg/plot), minimum number umbel per plant (67.26), and also minimum number of main branches (3/8) were obtained with maximum plant density. While minimum yield (1/315kg/plot), maximum umbel per plant (166.86) and maximum number of main branches (7/3) were obtained with minimum plant density.
