There are many results concerning the phenomena of preflare activity and coronal mass ejections (CME) formation. The situation is possible that the CME is the flare response or on the contrary the CME onset initiates the flare. In a number of recent papers R.A. Harrison and his coworkers have shown that CME initiation is associated with weak soft x-ray emission. We have studied a possible connection between the solar microwave precursors and CME. Following this goal, during the period of 1989, 36.5 hour observational samples preceding solar flares were investigated. There were 8 events among them which preceded proton flares. Data have been obtained at four wavelengths (3.2 cm, 10 cm, 30 cm, 46 cm) at the Zimenki Station near Nizhny Novgorod (Russia). To investigate the precursors we used the classification accepted for the description of radio emission bursts in Solar Geophysical Data.