Competition and yield advantage of sunflower-summer legumes intercropping systems were studied at University of Arid Agriculture, Rawalpindi, Paki star, during surrùner 1994 to determine their feasibility for increased yield from the same resources. Sunflower-soybean and sunÏlower-mungbean intercrop ping systems gave the highest (I.38) land equivalent ratio, followed by sunflower-mashbean intercropping system (1.34). The three intercropping systems gave a higher combined yield than single cropping of component crops. Among the component crops, sunflower appeared to be the dominant with higher values for relative crowding coefficient, positive aggressivity, and higher competitive ratio. Sunflowers in the three intercropping systems showed similar behaviour for aggressiveness and competitive ratio. Also, the degree of competition offered by sllmmer legumes was very similar.