In order to study the effect on sunflower and cotton of the residue of some sulfonylurea herbicides, two randomized complete block design studies were conducted with ten treatments in four replications for both of plants. Treatments included: sulfosulfuron (Apirus), idosulfuron+mesosulfuron (Chevalier), chlorsulfuron (Megaton), sulfosulfuron+ metsulfuron methyl (Total), idosulfuron+mesosulfuron+ mefenpyr (Atlantis) where all of the herbicides were used in three doses, with a no-herbicide control. Soil was sprayed with the herbicides and the treated soils were transferred to the greenhouse after four months, and sunflower and cotton were planted in pots containing these soils. The length and dry weight of different plant organs (root, stem and leaf) and total dry weight were measured at the four-leaf stage. The results showed that the treatments had negative effects on most of the measured characteristics in sunflower and sulfosulfuron+ metsulfuron methyl and chlorsulfuron at the highest dose (44 and 22.5 g ai ha-1, respectively) had the most harmful effects on the sunflowerand reduced dry weight by 82.97% and 70.31%, respectively, in comparison with the control. Only the height and root length of cotton had been affected of the herbicides and sulfosulfuron+ metsulfuron methyl and chlorsulfuron at the highest dose had the greatest negative effects on the height and root length of cotton. In attention to the results obtained, we can conclude that sunflower is probably more sensitive than cotton towards sulfonylurea herbicide residue.