Abstract: A field experiment evaluated the effect of nitrogen and gibberellin pretreatment on growth and development of two cultivars (Topaz and Sancerre) of gladiolus corms during 2003 and 2004 in Al-Hassa, Saudi Arabia. The experimental soil was loamy sand and received four levels of nitrogen (0, 25, 50 and 75 kg N ha-1) applied as urea. Gladioli corms were presoaked for 24 h in the gibberellic acid (GA3) solutions at a concentration of 0 and 100 mg L-1. Mean stem height, number of leaves per plant, leaf area, shoot dry weight, number of corms per plant, corms dry weight and flower diameter increased significantly with nitrogen and GA3 treatment. A significant difference was observed between the performance of two cultivars and the Topaz proved superior to Sancerre in all growth parameters. This study also confirmed the higher potential of Topaz gladiolus established as a benchmark for nitrogen application rate of 75 kg ha-1 for gladioli in Saudi Arabia and suggested that high corm and flower yield of gladioli may be obtained when corms are soaked in GA3 solution of 100 mg L-1 before plantation.