A discrete neutron kinetics for periodically pulsed fast reactors is formulated in which the time behavior of the delayed neutron precursor concentrations is considered explicitly only just before and just after each power pulse. The power pulse is represented by a delta function and a general integration of the precursor equations between pulses is used. The difference equations obtained are well suited for use in digital simulation of pulsed reactors. An “inhour equation” for pulsed reactors is derived from the difference equations and is shown to reduce to the relation obtained from the period-averaged kinetics equations, if the deviation from pulsed criticality is small.