An experiment under greenhouse conditions was carried out to investigate the effects of growth substances and plant stimulants on growth of Zea mays cv. Cargill-525. Maize plants were sprayed days after sowing with gibberellic acid (GA) 100 ppm, ethephon (CEPA) 600 ppm, Agrostemmin 0.8 g.1-1, triacontanol 0.5 mg.1-1, and check treatment. GA 100 ppm increased plant height and reduced this effect latter. CEPA 600 ppm reduced maize plant height. Leaf number was reduced with GA application and presented a tendency of increased with CEPA treatment. GA reduced dry matter weight and ethephon increased dry matter weight of roots, stem and leaves of 'Cargill- 525' maize. Triacontanol promoted reduction on net assimilation rate and relative growth rate of maize plants. GA and CEPA presented a tendency of reduced leaf area ratio of Zea mays plants.