Many researchers have studied algae as a source of material having potential biological activities, not least because many marine algae extracts have strong antioxidant properties. In this study, we investigated the anti-inflammatory effects of Pyropia yezoensis extract (PYE) on RAW 264.7 cells by measuring nitric oxide (NO), reactive oxygen species (ROS), superoxide dismutase (SOD), catalase activity, inducible NOS (iNOS), cyclooxygenase-2 (COX-2), nuclear factor-kappa B (NF-κB), interleukin-1β (1L-1β), and tumor necrosis factor-alpha (TNF-α). PYE decreased the production of intracellular ROS dose-dependently and increased SOD and catalase activity in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. PYE significantly suppressed the production of NO and reduced the expression of iNOS, COX-2, and NF-κB. PYE treatment also inhibited the production of IL-1β and TNF-α significantly and reduced the phosphorylation of Akt and MAPK significantly in LPS-stimulated RAW 264.7 cells. These results suggest that PYE has potential anti-oxidant and anti-inflammatory activities.