The study was conducted in the coastal area of the Gulf of Riga at three stations (Ainaži, Saulkrasti, Mērsrags) from 1997 till 2010. Brown algae samples were collected at 3.0-m depth from a boat using scuba gear in August and September. The concentrations of metals (Cd, Pb, Cu, Ni, Zn) were determined by atomic absorption spectrophotometry method (model Spektra A 880), and of Hg by FIMS (Flow Injection Mercury System, Perkin Elmer). The aim of this investigation was to determine the concentration levels of metals (Hg, Cd, Pb, Cu, Ni, Zn) in the dominant species of macroalgae (