The genetic disease cystic fibrosis (CF) is characterised by loss of transepithelial salt and water transport caused by malfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl^– channel. A novel strategy to restore transepithelial Cl^– transport to CF epithelia is to use artificial Cl^– transporters to transfer Cl^– across the apical membrane of these epithelia. During studies of one family of artificial transporters, we sought a method to investigate their transport properties in a cell-free system. Besides planar lipid bilayers, giant liposomes have been employed for single-channel studies of ion channels (Keller et al. 1988). To evaluate the use of giant liposomes for electrophysiological studies, we studied wild-type human CFTR assessing the characteristics of the channel in this artificial environment. Using a modification of the method of Riquelme et al. (1990), we synthesised giant liposomes from the phospholipid asolectin by the dehydration/rehydration technique. For a source of wild-type human CFTR, we used membranes from Fischer rat thyroid (FRT) cells expressing wild-type human CFTR and incorporated them into liposomes by high-speed centrifugation. To study the behaviour of CFTR incorporated into giant liposomes, we used the excised inside-out configuration of the patch–clamp technique. We found that membrane patches excised from giant liposomes form high resistance seals (> 10 GΩ) that are stable over time and large voltage ranges and have baseline noise equal to or lower than that achieved with excised membrane patches from cell membranes. Like CFTR Cl^– channels recorded in cellular membranes, CFTR reconstituted in giant liposomes formed Cl^– selective channels that were regulated by cyclic AMP-dependent phosphorylation and intracellular ATP. Upon excision of membrane patches from some giant liposomes, we observed large conductance Cl^– channels. However, no channel activity resembling CFTR was observed before the addition of ATP (1 mM) and PKA (75 nM; n = 4). In one membrane patch containing a single CFTR Cl^– channel, at –50 mV we measured a single-channel current amplitude of –0.46 pA at 27°C and –0.52 pA at 37°C using a Cl^– concentration gradient ([Cl^–]_intra = 148 mM, [Cl^–]_extra = 10 mM). At 37°C, the gating behaviour of this channel resembled that of CFTR in a cellular environment with bursts of openings interrupted by brief closures and separated by longer closures between bursts. We interpret our data to suggest that CFTR incorporated into giant liposomes retains many of its characteristics. However, the different lipid environment influences channel behaviour. We will now use this technique to study the activity of other Cl^– transporters in a cell-free system.