The capabilities of crystallization and extraction methods for separation of vanillin and syringaldehyde are described. Crystallization methods are based on differences in solubility of aldehydes ammonia derivatives in water, and solubility of their potassium salts in concentrated aqueous solutions of potassium carbonate. Temperature dependencies of solubility of potassium vanillate and potassium syringate in aqueous solutions containing 300500g/l of potassium carbonate are presented. The crystallization methods give separation factors of ca. 50 and allow to isolate syringaldehyde from its mixture with vanillin by one-stage crystallization with yield over 95% and purity over 98%. Extraction methods have lower separation factors of 22.5.