The 'equal compartment-agar method' was used to evaluate the allelopathic potential of wheat (Triticum aestivum) cultivars on the seedling growth of field bindweed (Convolvulus arvensis) and rye (Secale cereale). The experiment was carried out during 2005 at the Weed Research Department of the Iranian Crop Protection Research Institute, in a factorial form on a completely randomized design with three replications. Wheat cultivars in four levels (Shiraz and Niknejad, as more competitive cultivars; Tabasi and Roshan, as less competitive cultivars) and the density of wheat seedlings on four levels − 0 (control), 8, 16 and 24 − were considered as factors. Mean comparison showed that higher seedling density (at 24) had the greatest effect on decreasing rye growth (seedling, radicle, and hypocotyl) and all of the wheat cultivars showed a decrease in seedling, radicle and hypocotyl length in comparison with the control. All the wheat cultivars, especially at the highest density, decreased seedling and radicle length, but increased the hypocotyl length of field bindweed.