Cajanus cajan is a seed legume grown in tropical areas. Its yield remains low due to the degradation of agricultural land and non-fertilization. This study assessed the effect of mineral and organic fertilizers on Cajanus cajan growth. The study was carried out on ferralitic soil in southern Benin. Four treatments were involved: control treatment (T0 = no fertilizer); T1: 10 g of NPK15-15-15 with 10 g of urea per slash; T2: 10 g of NPK15-15-15 and 10 g of urea per slash combined with organic fertilization; and T3: 5 g of NPK15-15-15 and 5 g of urea per slash combined with organic. Organic fertilizer, consisting of cow dung, was applied as a bottom dressing at a rate of 0.5 kg per slash. The four treatments were set up in a randomized complete block design with three replications. Data on plant height, number of leaves, collar diameter and number of branches were collected on the plants. The results showed that the treatments resulting from the combination of mineral and organic fertilizers significantly (P < 0.01) improved the growth and production of Cajanus cajan. Thus, the use of cow dung combined with NPK15-15-15 and urea as fertilizers for Cajanus cajan improves the growth of this plant species.