In vegetable farming, the reduction in the use of herbicides has been an important factor in the definition of the production system. The objective of this research was to evaluate crop yield of cauliflower cultivars grown on Urochloa decumbens straw mulch, as well as the effect of the association between straw and cultivars on weed management. The treatments were arranged in a 2 x 4 factorial scheme: two managements (with or without U. decumbens straw mulch) and four cauliflower cultivars (Barcelona, Bromus, Júlia and Lisblanc). The experiment used a randomized block design with four replicates. There was no interference of straw mulch on crop yield of cauliflower cultivars. Hybrids Barcelona and Júlia presented yields of 22.0 and 23.9 t ha-1, respectively, and they did not differ from each other. The Bromus and Lisblanc materials did not adapt to the edaphoclimatic conditions of the region, which resulted in reduced cultural control and high weed emergence after weeding. U. decumbens straw had high control of the weed community (581.2 pls m-2 - without straw and 8.3 pls m-2 - with straw). It is concluded that the U. decumbens straw as mulch is an effective tool in integrated management of weeds in cauliflower crops, without interfering with crop yield, and its potential to control weed community density is approximately 98.6%, at 22 days after transplanting. The adaptability of the cauliflower cultivar to the region has a high impact on weed management.