A simple analogue epochal ratemeter is described, which produces an output voltage linearly proportional to the number of impulses counted during a pre-set sample interval. This circuit is primarily designed for the analysis of changes in nerve cell firing rates following micro-iontophoretic application of drugs, and it performs the same function as the more complex and expensive digital equipment normally employed. Nevertheless the circuit is eminently suitable for continuous recording of the average firing frequency of any pulse source. A simple modification is also described which permits the circuit to generate cumulative count curves.