Forty-five species of marine benthic macroalgae were identified from the coral reefs of Rose Atoll, American Samoa (Rose Atoll Marine National Monument). The algal collections were made during the February 2002, February 2004, March 2006, and March 2008 Pacific Reef Assessment and Monitoring Program (Pacific RAMP) under the auspices of the U.S. National Oceanic & Atmospheric Administration (NOAA), Pacific Islands Fisheries Science Center (PIFSC), Coral Reef Ecosystem Division (CRED). The collections included 6 species of Cyanobacteria, 14 species of red algae, 4 species of brown algae, and 21 species of green algae. Nine species represented new records for the Samoan Archipelago (American Samoa and Samoa). Based on their occurrences, eight species of green algae were considered most broadly distributed among the stations during all four expedition years. The top three broadly distributed species were Halimeda taenicola, Halimeda micronesica,and Caulerpa cupressoides.