Two-phase local heat transfer measurements are made for forced-convective evaporation of oil-refrigerant (R-12) mixtures inside a horizontal tube, The experimental parameters cover the range of 0%, 2%, and 5% oil by mass flow; thermodynamic quality range of.002 to 1; heat flux range of 700 to 20,000 Btu/h•ft2(2.2X103to 6.3x104W/m2); evaporating pressures from 43 to 65 psia (.29 to.25 MPa); and mass flux range of 7X104to 5X105lbm/h•ft2 (3.4x105to 2.4X106kg/hr m2). A correlation is developed that predicts 86% of the heat transfer within an error of ±35% over this entire range. Flow maps for evaporation are also presented and discussed.Units: Dual