The aim of this study is to investigate the fatigue crack growth behavior with post weld heat treatments (T4) on transverse tungsten inert gas-welded Aluminum alloy 6013. All fatigue tests have been carried out using center cracked tension specimens at ambient temperature under a stress ratio of R = 0.3. The results revealed that various time of aging in T4 affects its mechanical properties, also the fatigue crack growth behavior as well. It has been observed that in the heat treated samples the crack growth rate is lower than that in the as-welded sample, but higher than the rate in the base metal. To be more specific, samples with 18 hours aging exhibit the highest tensile strength and fatigue resistance compared to the other heat treated samples. The probability assessment has also been used to determine the fatigue crack growth rate and a good linearity has been found.