Abstract We address simultaneous observations of eruptive prominences with two radioheliographs, SSRT at 5.7 GHz and NoRH at 17 and 34 GHz. Three events are presented: 1997 September 27, 2000 September 4, and 2001 January 14. We analyze them using images observed in microwaves, $\mathrm{H}\alpha$, images from Extreme ultraviolet Imaging Telescope on board Solar and Heliospheric Observatory (SOHO), and white-light images from Large Angle and Spectrometric Coronagraph (SOHO/LASCO). We address three stages of the eruptive process: 1) pre-eruptive ascent, 2) rapid acceleration, 3) free expansion, and the overall kinematics of the ejecta. We estimate the densities and kinetic temperatures of prominences, and also the velocities and accelerations of ejecta. The main body of a prominence is surrounded by low-density cool extensions mixed with the coronal plasma, but the transition from the cool prominence to the hot plasma is sharp. From microwave and LASCO observations with overlapping fields of view we identify a radio prominence and a core of a coronal mass ejection (CME). Their temperature remains at about 5000 K, while the brightenings observed in extreme ultraviolet are probably due to only skin-heating. We discuss the observations in terms of our Dual-Filament CME initiation model.