A dispenser for volatile liquids with a vapor collection system is disclosed which controls the rate of operation of a vacuum pump 118 so that a simple vacuum intake 148 disposed preferably inside, but not sealed with, the filler neck can be used to collect only the vapors displaced from the fuel tank 110 by the fuel 104. The vacuum pump 118 is controlled by a controller 114 which receives, from various sensors 124, 128, 132 and 136, signals representative of the fuel vapor/air ratio immediately outside the tank, inside the tank, and/or inside the vapor recovery conduit 122, and/or of the pressure relative to atmosphere inside the tank 110 and/or of the rate of flow of liquid being dispensed. Based on these input signals, the controller 114 operates the vacuum pump 118 at an optimal rate to collect fuel vapor displaced from the tank 110.