Laboratory investigations have been undertaken in order to determine the influence of major parameters on the process of leaching of metal values from ocean nodules by means of model “sea- water”, that is - acidified chloride solutions. The effect of leaching conditions, i.e. time, temperature, stirring rate, liquid/solid ratio and HCl concentration was examined on leaching efficiency. It was found that concentration of hydrochloric acid greatly influences leaching of metals from ocean nodules. At HCl concentration exceeding 4.0 M and at 30^oC of temperature all valuable metals were almost completely leached out from the feed. Elevation of the leaching temperature allowed for reduction of the initial HCl concentration. Deep-sea nodules studied in this work exhibited somewhat different leaching behavior that reported in the literature.