This study aims to examine the effect of the number of ducks on the growth and yield of paddy. This research was conducted in Paloh Village, Samalanga District, Bireuen Regency. This research started from July to November 2021. This study used a non-factorial randomized block design with three replications. The treatments of this experiments were the number of ducks per hectare, namely control (without ducks), 1,200 ducks.ha−1(3 ducks/Plot), 1,600 ducks.ha−1 (4 ducks/Plot), 2,000 ducks.ha−1 (5 ducks/ha Plot), 2,400 ducks.ha−1 (6 ducks/Plot), and 2,800 ducks.ha−1 (7 ducks/Plot). The experimental plots size were 5.0 m x 5.0 m and each plot was fenced with plastics. The observation parameters are plant heights, number of tillers, weight of ducks, weed population, number of snails, panicles numbers, panicles length, filled grain weight, empty grain weight, 1000 grains weight, yield potential, and rice yield. The results of this study showed the number of duck on paddy crops had a very significant effect on the parameters of plant height and the number of tillers at 30, 45, and 60 days after planting, filled grain, yield potential, rice yield, duck weight, number of snails, but had no significant effect on the plant biomass (dry weight) parameters, panicles number, panicles length, empty grain weight, and 1000 grain weight and was able to suppress weed populations accurately.