Abstract In a recent paper, Glaser et al. ((1988) Biochim. Biophys. Acta 940, 275–287) use an inappropriate formula for the current-voltage relation of a pore to analyze the data from an electroporation experiment. They proceed to use their data analysis to support their contention that the voltage dependence of the membrane conductivity is caused entirely by the nonlinearity of the current-voltage relation of the pores, changes in pore size and number being unimportant. This contention is no longer justified. The formula that Glaser et al. use is valid for a one-dimensional problem, but they apply it to a pore that has a three-dimensional structure. Although the corresponding one-dimensional problem can be reduced to quadratures, only upper and lower bounds on the conductivity can be found for the three-dimensional problem without solving a partial differential equation.