The effect of a temporally correlated afferent current on the firing rate of a leaky integrate-and-fire (LIF) neuron is studied. This current is characterized in terms of rates, auto and cross-correlations, and correlation time scale \(\tau_c\) of excitatory and inhibitory inputs. The output rate \(\nu_{out}\) is calculated in the Fokker-Planck (FP) formalism in the limit of both small and large \(\tau_c\) compared to the membrane time constant \(\tau\) of the neuron. By simulations we check the analytical results, provide an interpolation valid for all \(\tau_c\) and study the neuron's response to rapid changes in the correlation magnitude.