The frequency response of the combined sensor and air-sampling system of an electrochemical ozone solde has been determined by means of a digital Fourier analyzer. The measured frequency response can be represented by a first-order process and a diffusion process in series. If the mean ozone concentration at the input is below a certain level a fraction of the ozone passes through an additional diffusion process. The variation of the frequency response as a function of the solution temperature and the background ozone level was determined for the ranges of interest. A satisfactory physical interpretation for the behavior of the frequency response is given. If the frequency response of the sensor is known, the ozone soundings may be compensated for it by deconvolution; this results in a highly improved correspondence between ascent and descent profiles.