Disperse dyes are the most common allergens among textile dyes. It is not known whether the purified dyes, impurities in the commercial dyes, or metabolites are the actual sensitisers. Moreover, it is not known whether those disperse dyes that are now present in test series are actually used in textile dyeing today. The aim of this work was A) to evaluate the significance of the impurities found in the commercial dyes Disperse Orange 1 and Disperse Yellow 3 and their potential metabolites from azo reduction regarding allergy; B) to investigate the sensitising capacity of Disperse Orange 1 and its metabolites and their cross-reactivity to Disperse Yellow 3, its metabolites, and p-phenylenediamine; and C) to determine whether eight disperse dyes, hitherto the most widely quoted as allergenic, are still used in textiles sold in various countries all over the world. Evaluation of the many published studies on contact allergy to disperse dyes used for dyeing textiles was also performed. These investigations provided interesting results, which could be useful for professionals working in dermatology, contact allergology, toxicology fields as well as to textile industry chemists.