We estimate the contribution of extragalactic radio sources to fluctuations in sky temperature over the range of frequencies (10-300 GHz) used for Cosmic Microwave Background (CMB) anisotropy measurements. CMB anisotropy observations at high resolution and low frequencies are especially sensitive to this foreground. We have compiled a catalog of 2207 bright radio sources, including 758 sources with flux measurements at 90 GHz. We develop a method to extrapolate the source spectra and predict

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... maps of extragalactic radio sources at instrument resolutions of 10 − 10 • FWHM. Our results indicate that the brightest radio sources will dominate microwave anisotropy for a wide range of resolutions and frequencies. Our skymaps predict the location and flux of the brightest radio sources at each frequency, making it straightforward to develop a template for masking the pixels containing them. This masking should be sufficient to protect high resolution CMB anisotropy observations from unacceptable radio source confusion.