The free amino acid content of Indian meal moth (Plodia interpunctella HUBNER) was analysed at various developmental stages by means of paper chromatography. 1) The free amino acids : present are alanine , arginine, aspartic acid, glutamic acid, glycine, histidine, leucine, methionine, proline, serine, threonine, tyrosine and valine. 2) Proline was detectable only in the acid-hydrolyzed Indian meal moth. 3) Arginine was clearly detected only in the larva stage. 4) Tyrosine methionine and valine were increased in the pupa stage. 5) Serine, glycine and tyrosine were present in high concentration in all stages.