The present study was performed during the two seasons of 2004 and 2005, to investigate the responses of growth characters, leaf water relations, chemical composition and yield of common bean (Phaseolus vulgaris L.) cultivars (Giza 6 and Bronco) to different plant growth regulators (gibberellic acid, naphthalene acetic acid and kinetin). Two pot experiments were carried out to evaluate the effect of 0, 10, 20 and 30 mg/l GA₃, NAA and KIN as a foliar spray. The obtained results revealed that applying GA₃, NAA and KIN at all rates caused significant increases in vegetative growth characters, i. e., root length, plant height, number of leaves, leaflet length and width, leaf area and dry weight of roots as well as shoots. In this respect, best results were recorded by GA₃ at rate of 20 mg/l, which led to the maximum significant increment in vegetative growth characters under study. Both cultivars showed significant increases in all tested growth characters under different growth regulator treatments. The growth characters in cultivar Giza 6 showed significant higher mean values particularly under 20 mg/l GA₃ than that of cultivar Bronco. Spraying bean plants with all rates of GA₃, NAA and KIN significantly increased RWC%, photosynthetic pigments (chl. a, chl. b, chl. a+b and carotenoids), total soluble sugars, total carbohydrates, total free amino acids, total protein and minerals (N, P and K⁺) concentrations in bean leaves. The optimum increment was observed by GA₃ at rate of 20 mg/l, NAA and KIN at rate of 30 mg/l. On the other hand, LWD% and total phenols concentration were significantly decreased in relation to different growth regulator concentrations. The effect of growth regulator treatments on the chemical components was more pronounced in cultivar Giza 6 than that of cultivar Bronco. Yield and its components as represented by number of pods/plant, weight of pods/plant, pod length, pod width and number of seeds/pod were significantly improved in response to all plant growth regulator treatments compared with untreated plants. In this regard, the application of GA₃ and NAA at higher level (30 mg/l) was more effective in enhancing yield and its attributes compared with the other growth regulator treatments. Moreover, cultivar Giza 6 successively increased yield and its composition mean values compared with cultivar Bronco, especially under high plant growth regulators level (30 mg/l).