The objective of this work was to evaluate the performances of Tanzania and Mombaça grasses intercropped with stylosanthes Campo Grande and Mineirão, and the proportion of legumes in the system over time. Eight treatments were evaluated: 1: Panicum maximum cv. Mombaça, 2: Panicum maximum cv. Tanzania, 3: Stylosanthes guianensis cv. Mineirão, 4: Stylosanthes macrocephala + capitata cv. Campo Grande, 5: Mombaça + Mineirão, 6: Mombaça + cv. Campo Grande, 7: Tanzania + cv. Mineirão, 8: Tanzania + cv. Campo Grande, studied in 4 cycles at two times of the year. The heights, the leaf/stems relation and the number of tiller of the grasses, cultures growth rate and the percentage of present legumes in the system were measured. No influence of the legumes under the characteristics of grass was observed. The legumes diminished the botanical composition of the pasture throughout the year. The performance of the grasses was affected by the time of the year and the structure of the plant for the management of the imposed residue height. The intercrop of Tanzania and Mombaça grasses with the stylosanthes Campo Grande and Mineirão, under intensive production system, was not sustainable. [ABSTRACT FROM AUTHOR]