We have obtained IUE low-dispersion spectra and optical ITS scans of the semidetached Algol-type binary system RX Gem. We have determined the spectral type of the primary component to be AO, with good accuracy. Since the primary eclipse is only partial, the spectral type of the cooler component has been determined with less accuracy as K2 (± 2). The system is only slightly reddened: its color excess is E (B -V) = 0.04 ± 0.01 mag. Two models of the system are considered, depending on the

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... ty class of the hotter star. We prefer luminosity class V, in which case the distance to the system is near 450 pc. However, a giant primary and larger distance are not excluded. There is evidence for circumstellar matter in deep shell-absorption lines seen in the ultraviolet. Optically, the system is a Be star, since it displays Balmer line emission, visible most clearly during the primary eclipse. The ultraviolet spectrum observed near mideclipse does not display the expected "W Serpentis-type" emission lines. Probably the main reason is that the primary eclipse is only partial. A need for a revision of the photometric elements is suggested by our eclipse observations, and new radial-velocity observations are badly needed.