An improvement in the process for the production of 1-amino-4nitroanthraquinone-2-carboxylic acid from 1-aminoanthraquinone-2carboxylic acid by reaction with formaldehyde in concentrated sulfuric acid and nitration of the reaction product into 1,2dihydro-6-nitro-7,8-diphthaloyl-3,1,4H-benzoxazone-4 followed by hydrolysis of the same. The improvement consists in precipitating the benzoxazone derivative by adding a precipitant, hydrolyzing the isolated benzoxazone derivative in aqueous solution and precipitating the 1-amino-4-nitro-anthraquinone-2-carboxylic acid from the alkaline solution by acidification. 1-amino-4nitroanthraquinone-2-carboxylic acid is obtained in a purity of 95 percent by weight or more.