Utilizing tax buoyancy and tax elasticity, this study evaluates the performance of the Philippine tax system from the perspective of tax mobilization. While earlier studies have been done on the Philippine tax system using these two measures, this paper updates and improves on these approaches by presenting computed elasticity estimates based on the 1975-1985 tax revenue series of the Ministry of Finance. These estimates employed the proportional adjustment method and the dummy variable technique of adjusting the revenue data for discretionary effects.