During a research cruise of the New Zealand research vessel Tangaroa 1974 large manganese nodule fields with high density have been discovered in the Southwest Pacific. The chemical analysis was carried out on the dredges showing average grades of 16.7% Mn, 21.1% Fe, O, 22% Cu, o, 4o% Ni and O, 38% Co. The highest copper and nickel contents are at l% and therefore below the limit of 3%, which must be exceeded in general today, when the ore is to be regarded as an economically interesting . Comparisons of different analysis of manganese nodules size fractions showed that there are little differences in the chemical composition associated with nodule size. Also, the value of metal content in well-preserved nuclei volcanogenic nuclei is comparable with that of the nodule surface areas.