The surface tensions of 1,1,1,2,2,3,3,4,4-nonafluorohexane (CF3CF2CF2CF2CH2CH3) and 1,1,2,2-tetrafluorot!tliyl-2,2,2-trifluororoethyl ether (CHF2CF2OCH2CF3), which are potential alternatives to HCFC solvents, were measured by the differential capillary-rise method. 20 data points for 1, 1, 1,2,2,3,3,4,4-nonafluorohexane and 17 dam points for 1,1,2,2-tetrafluoroethyl-2,2,2-trifltioroethyl ether were obtained in the temperature range of 289-348 K. The experimental uncertainties of temperature and Surface tension measurements were estimated to be within 20 mK and 0. 14 mN - m(-1), respectively. Surface tension correlations for 1, 1, 1,2,2,3,3,4,4-nonafluorohe,.ane and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether were formulated and were found to reproduce the present data within the limits of experimental uncertainty.