The invention is directed to a method for checking the operability of a tank-venting system. The tank-venting system includes a tank, an adsorption filter having a tank-venting line, a connecting line for connecting the adsorption filter to the tank, a tank-venting valve and a valve line connecting the adsorption filter to the tank-venting valve. A pressure source is provided for introducing a pressure into the tank-venting system, an operating characteristic variable of the pressure source is detected only over a pregiven time interval (.DELTA.t.sub.m) when introducing the pressure to obtain a time-dependent trace of the operating characteristic variable. The time-dependent trace is extrapolated and a conclusion is drawn as to the presence of a leak therefrom.