The seismic cycle requires that faults strengthen (heal) between earthquakes, and the rate of this healing process plays a key role in determining earthquake stress drop(1-4), rupture characteristics(5,6) and seismic scaling relations(2-4,7). Frictional healing (as evidenced by increasing static friction during quasi-stationary contact between two surfaces(1,8-12)) is considered the mechanism most likely to be responsible for fault strengthening(2,3,13,14). Previous studies, however, have shown a large discrepancy between laboratory and seismic (field) estimates of the healing rate(2-4,14,15); in the laboratory, rock friction changes by only a few per cent per order-of-magnitude change in slip rate, whereas seismic stress drop increases by a factor of 2 to 5 per order-of-magnitude increase in earthquake recurrence interval, But in such comparisons, it is assumed that healing and static friction are independent of loading rate, Here, I summarize laboratory measurements showing that static friction and healing vary with loading rate and time, as expected from friction theory(16-18). Applying these results to seismic faulting and accounting for differences in laboratory, seismic and tectonic slip rates, I demonstrate that post-seismic healing is expected to be retarded for a period of several hundred days following an earthquake, in agreement with recent findings from repeating earthquakes(13,14,19,20).