Two field experiments were carried out during two successive seasons of 2005/06 and 2006/07 at the Agricultural Production and Research Station, National Research Centre, El Nubaria Province, El Behaira Governorate, Egypt. The experiments aimed to study the effect of ascorbic acid or nicotinamide as soaking grains with 10 and 20 mg/l or as foliar spraying with ascorbic acid at 100 and 200 mg/l or nicotinamide at 25 and 50 mg/l on wheat plants. The results indicated that, different treatments of ascorbic acid or nicotinamide induced increments regarding plant height, dry weight, relative water content (RWC) as well as photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids)  compared with control plants. Moreover, the applied treatments increased yield and yield component traits (spike length, spike weight, spikelets and grains number/spike, grains weight/spike, spikes number/m², 1000-grains weight as well as grains; straw and biological yield (ton/fed). Also, the results showed increases in polysaccharide, total carbohydrates, total soluble-N and crude protein contents of the yielded grains. Moreover, application of ascorbic acid or nicotinamide increased amino acid content compared with control plants. The predominant amino acids were glutamic acid and proline. This study reveals that pre-soaking or spraying of wheat plants with ascorbic acid or nicotinamide could effectively enhance growth and increase productivity of plant as well as improving the chemical constituents of the yielded grains.