The use of linseed oil cake as an adsorbent for selected dyes was examined. The cake did not adsorb Acid Blue 158 or Reactive Red 184. However, it was an effective sorbent for Basic Blue 41. The Langmuir equation described the adsorption well. The enthalpy of adsorption was found to be endothermic and the capacity of the linseed cake for the dye decreased with increasing temperature. The linseed cake was compared with peat and it was found that it had a greater capacity for the dyestuff than peat. Although the Freundlich equation described the adsorption of the dye by peat, the data for the linseed cake gave curved relationships.