Temperatures and angular diameters are derived for 114 F-M stars using the infrared flux (IRFM) method and initially both the Vega flux calibrations of Dreiling and Bell (DB), and of Mountain et al. (1985). The DB calibration gives a significantly smaller variation of temperature with wavelength (0.10%) than the Mountain one (1.59%), and we adopt the DB one for the final results. Apart from a few substantial deviations, the temperatures agree well (standard deviation 0.12%), for overlapping stars with the adopted temperatures of Bell and Gustafsson using synthetic colours. Plots of temperature against V-Kn, where Kn is a narrow band filter in the K region, show a mean standard deviation in temperature of 0.46%. It is suggested that the temperatures have an order of accuracy of better than 1 %, but the accuracy is critically dependent on that of the infrared calibration of Vega, which remains uncertain. The possibility of using IRFM angular diameters as a method of detecting unresolved binary stars is discussed.