Purpose: Intercropping of two leguminous species at three planting densities and rainfed coconut trees was evaluated for green manuring in sub-humid region. We hypothesize that Mimosa caesalpiniifolia Benth. (M. caesalpiniifolia), native to the semi-arid region, would show better performance when compared to the exotic Gliricidia sepium Jacq. (G. sepium) at low planting density.Methods: A field experiment was conducted in Ceará, Brazil, in randomized blocks and 2 × 3 + 1 factorial scheme with four replicates. Treatments consisted of the two leguminous species at low, medium and high planting densities, in addition to a control. Two pruning cycles were carried out, followed by leguminous biomass deposition over the soil. Nutrients accumulated in pruning biomass and added to the soil, coconut trees nutritional status, fruit weight, and economic indicators were determined.Results: In the second pruning cycle M. caesalpiniifolia was surpassed by G. sepium, which accumulated in its biomass 673.0, 77.0, 428.1, 68.3 and 37.2 kg ha−1 of N, P, K and Ca, respectively at medium density. This resulted in higher soil contents of K and Ca (0.34 and 1.58 cmolc kg−1, respectively) at medium and high densities. Regardless of planting density, both leguminous species, compared to the control, increased the leaf N content in coconut trees by 2.2 g kg−1 and led to the highest Mg content (1.8 g kg−1). The total nutrients accumulated in G. sepium at high density resulted in higher financial value (5,074.6 US$ ha−1).Conclusion: G. sepium at high planting density has better performance than M. caesalpiniifolia for intercropping system with rainfed coconut in sandy soil of sub-humid region.