In this study, the creep behavior of AA3003 alloy extrusions with various manganese contents in solid solution and different microstructures was discussed. Tensile strength decreases with annealing time at 400 degreesC in spite of fibrous or recrystallized structures. These microstructures do not change during annealing. The specimen with high manganese contents in solid solution shows higher creep strength than that with low manganese contents in solid solution even if tensile strengths are same at 200 degreesC. Further, in the same manganese contents in solid solution, the specimen which has the fibrous structure indicates higher creep strength than the recrystallized one because of subgrain formation.