ABSTRACT The effects of organic fertilizer “cow manure” applications on quantitative and qualitative traits of hot pepper (Capsicum annuum L.) evaluated under field conditions. Treatments consisted of four levels of cow manure (0, 5, 10, and 15 t ha−1) for both the 2017 and 2018 growing seasons. The results indicated that cow manure applied at 15 t ha−1 resulted in the highest number of fruits per plant, antioxidant activities, and carbohydrate contents. At the same time, the lowest values were recorded in the control treatment in 2017 and 2018 (respectively). In both years, the highest plant height, number of lateral branches, number of nodes, fruit yield per plant, fruit fresh weight, and total flavonoids were obtained in 10 t ha−1 of cow manure treatment. The lycopene contents were 47 and 60% higher in 5 t ha−1 of cow dung fertilizer than control treatments in both seasons. The minimum β –Carotene was recorded in control, and the maximum was observed in 5 t ha−1 of cow manure fertilizer in both years. The results confirm that cow manure positively affects hot peppers’ vegetative and reproductive traits and antioxidant activity under field conditions.