Atherosclerosis is a chronic and progressive inflammatory disease. Novel anti-inflammatory therapies may have promise as treatment strategies for cardiovascular risk reduction. Rosemary (Rosemarinus officinalis L.) has been used in folk medicine to treat headaches, epilepsy, poor circulation, and many other ailments. It was found that rosemary could act as a stimulant and mild analgesic and could reduce inflammation. However, the mechanisms underlying the anti-inflammatory and antiatherosclerotic effects of rosemary need more study. This study investigated effects of the rosemary components, carnosic acid (CA), and carnosol (CAR), on cell migration. Monocyte chemoattractant protein-1 (MCP-1) and matrix metalloproteinase-9 (MMP-9) were determined by Western blot and gelatin zymography, respectively, in RAW 264.7 macrophages and vascular smooth muscle cells (VSMCs). VSMC migration was assessed by a Matrigel migration assay. Active compounds of rosemary extracts were also analyzed using a reversed-phase high-performance liquid chromatography. MMP-9 and MCP-1 activities were markedly diminished with methanol extract (RM), n-hexane fraction (RH), and CA in RAW 264.7 cells. RM, RH, CA, and CAR suppressed tumor necrosis factor-alpha-induced VSMC migration by inhibiting MMP-9 expression. Chromatograms of RM- and RH-containing CA and CAR revealed higher CA contents of RM (9.4%, 93.85 μg/mg dry wt.) and, especially, RH (18.4%, 184.00 μg/mg dry wt.), which were appreciably elevated compared with the similar CAR content in RM and RH (3.7%, 37.30 μg/mg dry wt.; and 2.5%, 25.05 μg/mg dry wt., respectively). Rosemary, especially its CA component, has potential antiatherosclerosis effects related to cell migration.