A study was carried out to determine the influence of nitrogen (N) sources on the growth and nitrate (NO₃⁻) accumulation of lettuce iceberg (Lactuca sativa) in nutrient film technique (NFT). Plants were supplied with treatments NO₃⁻ and six amino acids (AA)treatments, [glutamic acid (Glu), glutamine (Gln), alanine (Ala), glycine (Gly),aspartic acid (Asp) and argnine (Arg)]  , at three NO₃⁻-N/AA-N ratios:(1) 100:0, (2) 80:20 and (3) 60:40.The total N concentration was 12.5 mmol L^-1 for all treatments in nutrient solution. All AAs reduced plant growth with decreasing NO₃⁻ -N/AA-N ratios compared to the 100% NO₃⁻ treatment. Fresh and dry weight of shoot and root were significantly lower in Glu treatment than in all other treatments when NO₃⁻-N/AA-N ratios were 80:20 and 60:40. Decreasing NO₃⁻ -N/AA-N ratios reduced NO₃⁻ concentrations in fresh shoot, regardless of AA sources. Plants grown in (Glu) treatment had lower NO₃⁻concentrations in fresh shoot than grown in all other treatments when NO₃⁻-N/AA-N ratio was 80:20 only.