A wash composition comprises an N-long-chain-acyl dipeptide or salt in which the dipeptide moiety is composed of acidic amino acids, and an N-long-chain-acyl acidic amino acid or salt. Embodiments of the composition may exhibit low irritation and an excellent resistance to hard water, be free from the turbidity and odour found in natural peptides, and have an excellent feeling upon use without any creaking feeling of the hair or stretching feeling of the skin.