Factors such as the selection of cultivars and the planted density affect the development and yield of peanuts (Arachis hypogaea L.). This study’s objective was to evaluate peanut cultivars’ agronomic behavior under three planting densities in the northeast of Peru. The design used was randomized complete blocks (DBCAs) with a bifactorial arrangement 4A × 3B (factor A, peanut cultivars; factor B, planting densities), forming 12 treatments with three replications per block. The results revealed that T3 (Huayabamba cultivar + density of 30 × 50 cm) stood out, presenting the most favorable means in the number of pods (16 pods), number of seeds per pod (five seeds), height at 90 days (22.7 cm), and yield (1850 kg/ha). Empty pods did not show significant differences between treatments. T8 (Chivita cultivar + density of 20 × 50 cm) indicated the highest number of branches (six branches); in the weight of 100 seeds, the Rojo Tarapoto cultivar was the most encouraging, adapting optimally to the three densities. In addition, T7 (chivita cultivar + density of 10 × 50 cm) showed the shortest days at flowering and harvest, with 64 and 134 days. The study showed that T3 was the most efficient in pod and seed production, making it crucial to optimizing peanut yield.