Soil and groundwater at a former pesticide factory in southern Brazil was contaminated by chlorobenzene and benzene, and we evaluated phytoremediation using trees. In a greenhouse experiment, we exposed Eucalyptus urograndis, Pinus taeda, and no-plant controls to an aqueous solution of chlorobenzene and benzene (50 mg L-1 each). Both trees enhanced contaminant mass removal from 5 to 50% relative to no-plant controls. In a field experiment in Brazil, the planted Eucalyptus urograndis reached 5 m height within one year in the presence of these contaminants. We estimate these trees could remove up to 4.53 and 0.93 kg year-1 of chlorobenzene and benzene, respectively, in the field experiment. Our work suggests Eucalyptus urograndis and Pinus taeda are strong candidates for accelerating the remediation of chlorobenzene and benzene in soil and shallow groundwater.