Abstract: The competitive ability of C. dactylon with four different crops in two densities was assessed under glasshouse conditions. Four separate experiments were established using soybean [Glycine max (L.) merr.] Cv. Hernon-147, spring wheat (Triticum aestivum ) Cv. Alexandria, faba bean [Vicia faba (L.)] Cv. Banner and maize (Zea mays) Cv. Dekalb 198, which were grown as monocultures and in (1:1) additive mixtures with C. dactylon. Result have shown that competition reduced dry weight of both crops and C. dactylon by about up to 44 and 52%, respectively. Maize root dry weight was severely (72% reduction) affected by C. dactylon. However, faba bean, soybean and wheat were stronger competitors to C. dactylon.