The effects of cooling and warming on neural function are reviewed. The literature is presented progressively from the subcellular through the cellular level to the neural systems level. Temporal measures relevant to membrane activity, action potentials, synaptic transmission and evoked potentials are all consistently increased with cooling and decreased by warming. The various measures of amplitude at difference levels, and even within similar preparations, however, are contradictory: some laboratories report increased amplitudes with cooling and others decreased amplitudes under similar conditions. Emphasis is given to identifying-factors which may resolve the differences. These include: (1) the rate of temperature change, (2) sites of cooling, stimulation and recording, (3) stimulus characteristics, and (4) fundamental differences in temperature sensitivities of different neural tissue. Aside from amplitudes, traditional methods and refined methods of predicting neural response to temperature are good.