Abstract: The objective of the present study was to quantify the effects of zeolite application and allophanic soil (KyP and KnP) on leaf area development, plant height and reproductive morphology of soybean. One determinate (Enrei [MG] 1V) and indeterminate cultivar (Harosoy [MG] 11) were planted in pots on April 20th at the Faculty of Agriculture, Ehime University, Matsuyama Japan during 2007. Zeolite levels of 0, 1 and 2 wt.% were used to determine the growth behavior of soybean cultivars grown on two allophanic (KyP and KnP) and a paddy soil. Zeolite application and allophanic soil significantly affected leaf area development, plant height and reproductive morphology of soybean cultivars. Maximum leaf area and plant height were obtained from 2 wt.% zeolite application and allophanic soil (KyP and KnP). Minimum number of days to flowering, pod formation, seed filling duration and physiological maturity were taken by 1 and 2 wt.% zeolite application in both cultivars. The same trend was observed in number of days to reproductive development by KyP and KnP allophanic soil. Enrei took maximum days to all reproductive stages as compared to Harosoy. Zeolite treated plots and allophanic soil (KyP and KnP) attained more plant height than control plots grown on paddy soil without zeolite application. Harosoy produced the tallest plants than Enrei. Present findings supported the results of experiments by demonstrating that zeolite application at planting time promotes leaf area, plant height and encourage the reproductive morphology of soybean cultivars grown on KyP and KnP allophanic soil.