Using a GCM fitted with tracer diagnostics, we examine how continental moisture recycling affects the stable water isotope content of precipitation, focusing on its contribution to the ''noise'' in the well-established relationship between temperature and Δ18O. On a global basis, for temperatures between -30¿ and 15 ¿C, continental recycling explains more than a third of the variability in annual Δ18O that is not explained by temperature. Recycling appears almost as important as temperature in defining Δ18O distributions during northern hemisphere summer. ¿ American Geophysical Union 1993