D56 or D 56 may refer to:
* D56 road (Croatia), a state road in Croatia
* D 56 road (United Arab Emirates) in Muhaisnah, Dubai Emirate
* GER Class D56, a class of British steam locomotives
and also:
* the ICD-10 Chapter II: Neoplasms; Chapter III: Diseases of the blood and blood-forming organs, and certain disorders involving the immune mechanism, ICD-10 code for thalassemia
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