Austenitic stainless steel welds typically have duplex microstructure with a few to over 10 ％ of 8-ferrite in austenite to prevent hot cracking during solidification. Therefore, austenitic stainless steel welds are also susceptible to thermal aging embrittlement similar with cast duplex stainless steels (CDSSs). Although microstructural morphologies of 8-ferrite in austenitic stainless steel welds is different from that of CDSSs, the effect of that on an thermal aging embrittlement behavior is not fully known. In this study, the effect of microstructural anisotropy on a thermal embrittlement of welds has been investigated. Charpy absorbed energy decrease ratios with thermal aging depends only on the ferrite content, whether weld metals or cast duplex stainless steels. It has been suggested that the previous knowledge about thermal aging behavior of duplex stainless steels can be applicable for that of stainless steel welds.