Type 13Cr martensitic stainless steels are widely used for threaded and coupled oilfield casing and tubing because of their resistance to corrosion by dissolved carbon dioxide and their cost advantage over most other corrosion-resistant alloys. However, 13Cr used for welded downhole components requires careful planning. Their high hardenability creates a hard heat-affected zone microstructure, which must be tempered by post-weld heat treatment (PWHT) to recover the alloy’s limited resistance to sulfide stress cracking. At the same time, the relatively high strength of downhole 13Cr stainless steel grades (80 to 110 ksi specified minimum yield strength) requires tempering temperatures that limit the maximum PWHT temperature that can be applied without compromising the material’s strength. This publication presents welding procedure qualification of 13Cr grades and experimental work performed to determine how PWHT affects the yield strength of 13Cr grades. Methods are described for establishing a suitable PWHT time and temperature for these alloys.