Speleothems are regarded as major palaeoclimate and palaeoenvironmental archives, notably because of their records of oxygen and carbon isotopic variations, which arc constrained in a reliable chronological framework with U-series dating. Increasingly studied, these isotopic signals are, however, complex and their interpretation must be based on a good knowledge of the isotopic fractionation conditions during calcite precipitation and of the context of speleothem formation. This paper presents a bibliographic review of the use of speleothem stable isotopes in palaeoclimate and palaeoenvironmental reconstruction. The physico-chemical processes that combine to determine the isotopic composition of the precipitated calcite arc first presented. Then, the limits and uncertainties associated with the interpretation of these isotopic signals are discussed, along with the means by which to identify isotope signal disturbances.