Bankfull widths of steep headwater channels were examined in the Western Carpathian flysch midmountains. The criteria of the top of banks, scoured lines and presence of bank vegetation were helpful in the bankfull width determination. A direct downstream relationship between the parameters of the bankfull width and the watershed area and a negative downstream relationship between the parameters of the bankfull width and the channel gradient were observed in all examined channels similarly to lower gradient rivers. However, streams based in more resistant sandstone flysch and/or influenced by small debris-flows indicated much less dependence between these parameters. Significant differences in bankfull widths were found when channels of the same watershed areas, but located on leeward and windward hillslopes were compared.