We consider a method for the determination of the parameters of bioelectric impedance (BEI) based on transient-function data. We analyze the error in estimating the bioelectric impedance in order to determine the optimal parameters of a testing pulse: its front and its duration. It is determined that a key role is played by the time constant of the biological tissue that is being investigated, for the modeling of which we use the Cole circuit. As a result of our research we obtain functional dependencies that establish a connection between the error in determining the bioelectric impedance and the parameters of the testing pulse.