A fluid loss additive for hydraulic cement which includes at least two highly hydrolyzed polyvinyl alcohol resins having different molecular weights, or a polyvinyl alcohol resin composition having a broad molecular weight distribution. The fluid loss additive is suitable for use in cement slurries which may be subjected to elevated temperatures, as is common in oil and gas drilling operations. By way of the invention, cement slurries are provided which have improved fluid loss properties at high temperatures, while maintaining manageable rheologies that are conducive to mixing, pumping, and the like across a broad range of temperatures.