Shockley and Read[1] and Hall[2] (SRH) theory for electron hole recombination at traps is modified to include the effect of a finite time of relaxation before the captured electron or hole settles to the ground state. The modified expression for the recombination rate retains all the essential features of SRH theory and includes two additional effects: at low levels of injection lifetime shows a temperature dependence of the type τ = τn0+Cne−ΔEn/kT and at high injection the recombination rate saturates at an upper value Nt/δt where δt is relaxation time and Nt is density of traps.