Experimental heat transfer data for critical heat flux (CHF) during pool boiling of liquid metals are surveyed. CHF is found to be related to the stability of boiling prior to CHF. A new correlation is given for stable saturated boiling CHF and is shown to give better agreement with data than earlier correlations. This correlation is also applicable to nonmetals. A new correlation is also given for the lower limit of CHF during unstable boiling. Included in the correlation are data on sodium, potassium, cesium, rubidium, and mercury, on plates and cylinders. The limited data available for subcooled CHF are grossly overpredicted by correlations that have been successful for ordinary fluids.