To provide a method for producing 2,3-pyridinedicarboxylic acid, suitable for industrialization by which a high purity product is produced in high yield by effectively utilizing a waste liquid.

The method for producing the 2,3-pyridinedicarboxylic acid comprises (a) a step for oxidizing quinoline or 8-hydroxyquinoline in water in the presence of a copper ion, and crystallizing and separating a copper salt of the 2,3-pyridinedicarboxylic acid, (b) a step for reacting an alkali with the separated copper salt of the 2,3-pyridinedicarboxylic acid in water to provide an aqueous solution of the alkali salt thereof, and (c) a step for crystallizing and separating the 2,3-pyridinedicarboxylic acid by reacting a mineral acid with the obtained aqueous solution of the alkali metal salt of the 2,3-pyridinedicarboxylic acid. (A) The whole or a part of the aqueous solution obtained after separating the 2,3-pyridinedicarboxylic acid at the step (c) is used at least as a part of the water used in the steps (a) or (b), or (B) copper or a copper compound is added to the whole or a part of the aqueous solution to recover the 2,3-pyridinedicarboxylic acid in the aqueous solution as the copper salt, and the resultant aqueous solution is recycled to and used in the step (b).