In our study we studied pollution and heavy metal fractions in the Golden Horn (Istanbul, Turkey). This area has been exposed to domestic and industrial pollution for many years. Concentrations of Zn, Cr, Cu, Pb, Cd, and Ni heavy metals were determined in the study that was conducted to monitor the current state of pollution and changing conditions in the polluted estuary. Mean heavy metal concentrations were found as: Zn 70-260, Cr 26-110, Cu 70-135, Pb 8-50, Cd 0.1-2, and Ni 10-38 mg/kg. Results of the analysis showed that metal concentrations were usually low, indicating that the sediment was not too polluted in the present case. The range of ratios, different fractions of metal concentrations, and total metal concentrations in the samples were critical for potential toxicity and mobility of metals. Results of the analysis showed that heavy metal fractions in the sediment were usually found in residual forms. The values obtained in the study were also compared with the literature. It was found that surface sediments in the Golden Horn were less polluted than other areas. Establishment of sewer collectors and wastewater treatment plants has improved the heavy metal levels in the sediment.