Crop varieties that are more competitive with weeds offer a means of reducing dependency on herbicides. On the basis of trial results, economic analysis indicates that choosing crop varieties that have stronger competitive ability against weeds can provide a clear economic advantage for farmers. In this paper, the effect of changes in seeding rate on this economic advantage is explored. The question if whether it is economic to breed for greater competitive ability is addressed by examining the economic implications for the breeding program, in terms of costs and impacts on other selection traits, of selection for competitive ability. The results of the analysis indicate that more competitive varieties can be an important tool in an integrated weed management package. However, while breeding for increased competitive ability can produce benefits for weed control, in some cases the most appropriate option is agronomic practices such as increased seeding rates. Selection for increased competitive ability in a breeding program can reduce the rate of progress with other important characteristics such as yield. Only in particular circumstances is it economic to increase selection for competitive ability within a breeding program.