Abstract Studies of the amino acids distribution in plants subjected to nutrient regimes are limited. The present study investigated the effect of NO3‐N and FeSO4‐Fe regimes on chlorophyll and total amino acids composition of tomato and wheat plants. Also the distribution of 17 amino acids between the different plant parts was studied. Increasing the NO3‐N level up to 200 mg kg‐1 greatly increased the total amino acids content of tomato plants. The total amino acids content of wheat plants continued to increase with addition of NO3‐N up to 400 mg kg‐1. The response of chlorophyll content to NO3‐N supply was highly dependent on Fe level both in tomato and wheat plants. The interaction between NO3‐N and FeSO4‐Fe had a great effect on the total amino acids content and distribution. Iron increased the translocation of proline from roots to leaves. The overall amino acids contents of leaves was higher than that of stems or roots.