The interaction of sulfated polysaccharides--fucoidans from brown seaweeds Laminaria japonica, Laminaria cichorioides and Fucus evanescens with Toll-like receptors (TLRs) expressed on membranes of embryonic human kidney epithelial cells (HEK293-null, HEK293-TLR2/CD14, HEK293-hTLR4/CD14-MD2 and HEK293-hTLR2/6) was investigated. In vitro fucoidans specifically interacted with TLR-2, TLR-4, and the heterodimer TLR-2/6 resultated in activation of transcription nuclear factor NF-kappaB. Analysis of composition the hydrolyzed fucoidan from F. evanescens was carried out by gas-liquid chromatography and chromatography-mass spectrometry. Results indicated the absence of 3-3-hydroxytetradecanoic acid (3-OHC14), the basic component of lipopolysaccharides in the preparation. Thus, the obtained results suggested that fucoidans from brown seaweeds possessing immunotropic activity are independent ligands for TLRs, and are able to induce genetically determined biochemical processes of protection organisms against pathogenic microorganisms.