AbstractIt has been proposed that lovastatin arrests cells in the G1‐phase of the division cycle, and that release from lovastatin inhibition produces a synchronized culture. A new method of methocel time‐lapse‐videography has been used to analyse cell division patterns following lovastatin treatment. Release of L1210 cells from lovastatin inhibition failed to produce synchronized divisions. Moreover, contrary to earlier proposals, lovastatin did not arrest cells with a G1‐phase amount of DNA. Analysis of previous reports of ‘synchronization’ and growth‐arrest support these findings. It is concluded that lovastatin neither synchronizes cells, nor arrests cells in the G1‐phase of the division cycle.