This paper introduces farm-heterogeneity in measuring technical efficiency of Swedish dairy farms using farm-level data. In calculating technical efficiency which is allowed to vary over time and across farms, we control for farm-specific effects. This is possible only when panel data is available. Furthermore, we separate technical efficiency from technical change-the presence of which is indicated by a shift in the production function over time, ceteris paribus. We also calculate percentage change in technical efficiency to examine whether farm efficiencies have improved over time. Finally, a comparison of technical efficiency, elasticities of different inputs, and technical change is made across different years and panels. The data includes four panels of dairy farms observed during the period 1976-1988, excluding 1985. ©1994 Kluwer Academic Publishers.