Forced convection heat transfer from a cylindrical heating element with crossflow occurs in many situations of practical interest, but heat-transfer coefficients for liquids have been reported in the literature only for Reynolds numbers below 200. This paper correlates new data taken with water and ethylene glycol at Reynolds numbers from 40 to 100,000 and Prandtl numbers from 1 to 300. The effects of temperature differences large enough to produce significant changes in viscosity across the boundary layer have also been investigated and are correlated in terms of a viscosity ratio.