The distribution of Cd, Cu, Pb, and Zn in eelgrass (Zostera marina L.) was studied at three locations with different heavy metal loads in the Limfjord, Denmark.The eelgrass was fractionated into roots, rhizome, stem, and leaves according to age, and the heavy metal concentrations in each fraction were determined. The distribution patterns of the four heavy metals in eelgrass were independent of the heavy metal loads at the sampling stations. The concentrations of all metals were greater in the roots than in the rhizomes. In the aerial∗ parts two different age-dependent distribution patterns were observed. The concentrations of Cd, Pb, and Zn increased with age while the opposite was true for Cu. The distribution of lead correlated with the distribution of ash content. These age-dependent distribution patterns were maintained throughout the observation period and were most pronounced for Cu and Zn in winter.The heavy metal distribution in eelgrass is discussed in relation to gross morphology, especially age-structure. It is suggested that the accumulation of Cd, Pb, and Zn is due to a slow irreversible uptake or to the existence of more binding sites in old leaves. The distribution of Cu can be explained by translocation within the plant, dilution due to growth or leakage from the older leaves.