A very efficient synthesis of 3′-azido-3′-deoxythymidine (4) (AZT) from thymidine is described. The key step is a one-pot transformation of thymidine into 2,3′-anhydro-5′-O-(4-methoxybenzoyl)-thymidine (2) which is isolated by direct crystallization. Further ring opening of 2 with the azide ion and 5′-O-deprotection afforded AZT in 73 % overall yield.