Abstract: This study was conducted to determine the effects of different plant densities (20x50 cm, 30x50 cm, 20x100 cm, 30x100 cm) on plant growth characteristics and fruit yield of paprika pepper (Capsicum annum L.) in open field. Plant height, leaf chlorophyll content, flower number, yield, fruit seed number, 1000 seed weight and vitamin C were assessed at immature and mature. The results indicated that vegetative growth characteristics (plant height, lateral stem length and leaf chlorophyll content) reduced as plant density increased. The highest lateral stem number and leaf number were obtained in plants density 30x100 cm. Plant density affected on flowering factors (node number to first flower, days to 1st flowering and flower number). The days to 1st flowering increased as plant density increased. It was observed that fruit volume, fruit average weight, plant yield and seed number decreased with increasing plant density, but total yield ha-1 increased with increasing plant density. The highest and lowest of yield ha-1 were obtained by 20x50 cm and 30x100 cm spacing, respectively. Also plant density significantly affected on Vitamin C. The highest and lowest vitamin C were observed in 30x100 cm and 30x50 cm spacing, respectively.