The adsorption behavior of M(2+) ions (M = Cu, Co, Ni, and Pb) onto manganese nodules has been investigated at 3.5 less than or equal to pH less than or equal to 5,6 (acetate-acetic acid buffer) and 30 less than or equal to T (degrees C) less than or equal to 50. Under identical conditions the adsorption capacity for different metal ions increased in the order Ni2+ < CO2+ < Cu2+ < Pb2+. In all cases the extent of adsorption increased with increasing pH and temperature. The behavior of various metal ions released from manganese nodules during adsorption has also been discussed,