In this study we investigated whether early G1 cells can be collected by the method of centrifugal elutriation, and in particular whether the stringent growth regulatory properties characteristic of early G1 cells really are preserved in elutriated cells. We compared the cell cycle kinetics of elutriated Swiss 3T3 cells with unperturbed cells which had been analyzed by time-lapse video recording. Our data show that centrifugal elutriation yields a good synchronization of early G1 cells. However, from a strict cell cycle kinetic point of view the elutriated cells preserve their growth regulatory properties to a variable extent. This fact was explained by the finding that the early G1 cells tend to undergo a temporary G0 arrest as a result of the elutriation procedures.