Proteins with Ankyrin repeat motifs (ANK) are found to be associated with diverse biological processes and molecular functions in most of the studied organisms. Several studies have been done on the ANK-motif containing proteins of various model species, but similar studies on their counterparts in brown algae are not available. In this study, we have identified a total of 1,372 ankyrin repeats in 339 proteins of the model brown algae Ectocarpus siliculosus and the consensus sequence of the ANK repeats was determined. The proteins were classified into eight different subfamilies depending on their structural diversity. The data provided in this study may provide useful basis for future reverse genetics analysis of the members of this family.