Lysine availability in wheat flour and bread was determined by the growth response method on rats using regression analysis relating gain in body weight and/or in body water to lysine consumed at two extractions, 87% and 72%. The availability of nitrogen and of essential amino acids were also determined by the balance trials method (fecal analysis method) with rats. The results of growth method show that baking increases lysine availability on the basis of body water gain. Also extraction levels affect lysine availability on the basis of change in body water. Wheat flour and bread of 72% extraction has more lysine availability values than the 87% extraction on the basis of moisture gain. Results of balance trials show that neither the extraction level nor the baking has a significant effect on essential amino acids availability. A fairly good correlation is obtained for wheat flour and bread for the two extractions. Values of change in weight, food efficiency, PER, NPR and true digestibility showed that baking and level of extraction of wheat has no significant effect on the nutritive value of wheat investigated in the present study.