The preparation of a reversed-phase high-performance liquid chromatographic support by deposition and cross-linking of polybutadiene on the surface of microporous zirconia is described. It is demonstrated that acidic solutes undergo very strong interactions with the zirconia surface even in the presence of a thick polymer layer. These interactions can be minimized by the use of phosphate in the mobile phase, in which case the small solute retention characteristics of the polymer coated zirconia are comparable to alkylsilane-derivatized silica-based reversed-phase supports. Most importantly, the polymer-coated zirconia was stable in alkaline solution. There was no evidence for degradation of the support even when it was exposed to a mobile phase of 1 M sodium hydroxide at 100°C. In contrast, polybutadiene-coated alumina was not stable under these conditions.