Failure of anion transport across cell membranes causes diseases, such as cystic fibrosis. One therapeutic strategy is to replace dysfunctional anion channels with alternative transport systems. Although selective cation transporters are well known, until recently anion transporters were unavailable. We previously demonstrated that cholapods, molecules derived from cholic acid, bind anions with high affinity and promote anion efflux from liposomes [1]. In the present study, we characterised the cholapods AS09, LJ09 and TL145 using the planar lipid bilayer technique. Membranes were formed using a mixture of POPE/Cholesterol (7/3) plus cholapod at a ratio of 250:1 and were bathed in symmetrical anion-containing solutions (10 – 200 mM). Membranes were voltage clamped at 0 mV and 5-second voltage steps from -200 mV to +200 mV applied to the membrane. In response, currents relaxed to a steady state after an initial peak. Using steady state currents, I-V relationships were constructed and anion conductance calculated; using current relaxations, electrical relaxation analysis was performed [2]. All three cholapods conduct Cl – , NO3- and Br- . Transport is anion concentration-dependent and anion conductance decreases with increasing anionic radius. The Cl- and Br- conductances of AS09 are larger than those of TL145 and LJ09, whereas TL145 has the largest NO3- conductance; none of the cholapods conduct SO42- . The cholapods are highly anion selective and their anion permeability sequences are NO3- > Br- > Cl- . Typically, transporter-mediated ion transport across membranes involves four steps: (i) ion and transporter form a complex on one side of the membrane, (ii) movement of the complex across membrane to the other side, (iii) dissociation of the ion from the transporter and (iv) movement of the ion-free transporter back across membrane. The speed of these four steps is represented by four rate constants: KR, KMS, KD and KS, respectively. Our analysis reveals two important points. First, values of KMS of all the cholapods are smaller than those of other rate constants. This suggests that movement of anion-transporter complex across membrane is the rate-limiting step of cholapod-mediated anion transport. Second, for LJ09, values of KMS and KS are significantly smaller than those of AS09 and TL145. This provides an explanation for the small Cl- conductance of LJ09. We conclude that to develop better anion transporters, future studies should focus on improving the lipid solubility of cholapods, their charge-shielding properties and anion affinities.