Geochemical partitioning of Zn, Cu, Fe and Mn was determined in the coastal marine sediments of Mar de Plata (Argentina), to assess the degree of contamination and the metal chemistry. The sequential extractions were tested to be included in monitoring programmes of the coastal environments. Five sediment samples were collected in the coastal area near to the city of Mar del Plata and analysed for total metal concentrations by atomic absorption spectrophotometry. Sequential extractions were also performed, partitioning the metals into five geochemical fractions. Considering the distribution trends as observed from the heavy metal concentrations, two main sources were identified in the considered area: that related to Mar del Plata harbour (Station 5), and the area affected by the pre-treatment plant of the urban and industrial sewage disposal of the city (Station 2). The method has shown itself to be an excellent tool for environmental evaluation, and it would be desirable to include it in future programmes directed to assessing the health quality of aquatic ecosystems.