Abstract. When the series of voltage pulses is applied to a gas-filled discharge tube, one observes that a breakdown and the subsequent discharge will influence the probability of the next breakdown. Repeating the measurement of the breakdown delay time τ many times we can determine the distribution of τ and subsequently decompose breakdown delay time into a formative time lag and the statistical delay time. Our measurements show that even a measurement taken 10 min after the last breakdown is influenced by it. The processes in a volume being unimportant due to a flow mode of operation, it is proposed that the memory effect is caused by some surface processes. The experiments are carried out in a discharge tube with two plane-parallel electrodes separated by 2 cm in a pressure range of several Torr. In this paper, dependences of both statistical delay time and formative time lag on the repetition rate, discharge duration and anode voltage are presented.