The static and cyclic creep behaviors of base and longituinally welded AISI-304L stainless steel have been studied. The weld specimens were welded by SMAW (Shielded Metal Arc Welding) process, and crept under control load condition at 803-873 K using electro servo-hydraulic testing machine. The results of static and cyclic creep tests showed that longitudinally welded metal behaves like composite material. Using static and cyclic creep test results and tensile test data, the creep behaviors of welded metal were quantitatively analysed and compared with experimental results. In the case of static creep, the following equation was obtained between the creep rates of base and welded metal. (수식) In the case of cyclic creep, negative creep stages were observed at the initial cycling period. This negative creep strain were believed to be due to the cyclic hardening of base metal and the following relationship was satisfied. ΔεαΔσ_(base) Δσ_(base) : Cyclic hardening of base metal.