In a composition for forming an interfacial layer on a photoresist pattern, and a method of forming a pattern using the composition, the composition includes a water-soluble polymer, a cross-linking agent and a water-miscible solvent. The water-soluble polymer includes a repeating unit represented by Formula 1, wherein R1, R2, R3, R4 and R5 independently denote a hydrogen atom, a hydroxyl group, an alkyl group, a hydroxyalkyl group, an aminoalkyl group, a mercaptoalkyl group, an amino group, a mercapto group or an ammonium salt, R6 denotes a hydrogen atom or an alkyl group, m denotes an integer of 1 to 4 both inclusive, and x denotes an integer of 1 to 1,000 both inclusive. Also, at least one of R1, R2, R3, R4 and R5 is a hydroxyl group, a hydroxyalkyl group, an aminoalkyl group, a mercaptoalkyl group, an amino group, a mercapto group or an ammonium salt.