The purpose of this study is to investigate the current status of contamination due to the heavy metal and organic substances (PAHs, HC >12, organotin compounds, PCB, DDD, DDE, DDT) pollution of the sediments from the coastal area of the Bagnoli brownfield (Naples, Italy) and draw some hypotheses on the origin and trends of industrial and also geogenic contamination. Surface sediments and cores were collected and analysed. The results showed remarkable concentrations of heavy metals, PAHs, and other substances that are significantly higher than the national guideline values of sea sediment quality. Correlation analyses and spatial distribution analyses showed that generally the inorganic and organic pollutants have similar patterns, confirming the common origin from the industrial activity, but also that some of the studied metals have some natural contribution originated from the geologic setting of the area. The distribution of most of the heavy metals (especially Cd, Hg, Pb, Cu, Zn, partially Cr and Ni) and PAHs are similar, and the highest concentrations were recognised between and just off the piers, but a diffuse contamination is widespread up to the external areas of the site perimeter, rising concern on the diffusion of contaminants to the whole Gulf of Pozzuoli.