A light-sensitive composition for use with lithographic printing plates is described which comprises (1) a light-sensitive, organic solvent soluble and substantially water-insoluble diazo resin which is the reaction product of a water-soluble, light-sensitive condensate of an aromatic diazonium compound and an organic condensing agent with a halogenated Lewis acid or a salt thereof, (2) a substantially water-insoluble, film forming organic high-molecular weight compound having an acid value of from 10to 200, (3) a polynuclear aromatic sulfonic acid or a salt thereof, and (4) a salt-forming organic dye compound.