This review covers the chemistry of heterocyclic compounds published during 1999, but focuses on the synthesis of such compounds rather than their reactivity. The subject is divided according to ring size and further grouped according to reaction type or nature of the heterocycle to guide the reader through the diverse material covered. Solid phase synthesis has largely been omitted because of the abstracting of much of this material in J. Chem. Soc., Perkin Trans. 1.