New spectrographic observations of the eclipsing binary RS CVn show that the radii of the components are 8 per cent and the masses 22 per cent smaller than previous evaluations. The subgiant component, spectral type near K0 as estimated from its color, is slightly more massive than the smaller F-type star and does not fill the critical zero-velocity surface. Photometric observations show that the light of the subgiant, as observed during total eclipse, increased by 0.3 mag. between June, 1956, and January, 1959, with essentially no change in color and no corresponding increase in light at the quadratures. The light of this component, at least, varies intrinsically both with time and over its surface. The long-observed asymmetry of the light-curve outside eclipse is found to have the same color as the K-type subgiant. This persistent asymmetry could be caused by a slight pulsation with the same period as the orbital motion. Nearly continuous photometric observations of high precision are required to determine the behavior of the star. Because of the asymmetries and variations of the light-curve, definitive values are established only for the masses of the components and the color of the cooler star. Probable ranges of the various properties of the system are given in Table 7.