It was conducted an experiment in the Experimental Field of Horticulture Section of ESALQ, Piracicaba, to verify the effects of linuron, chlorobromuron, and chloroxuron on carrot crop. It was tested the minimum and maximum rates recommended by herbicide productors in "pré" and post-emergence of weeds. The herbicide did not interfy over carrot overground part. Generally, pre-emergence treatments gave higher production of overground part, roots and commercial roots than post-emergence treatments. Both linuron and chlorobromuron gave good results, without interfy over production, while the minimum rate of chloroxuron gave the least production due to poor weed control.