Constructed wetlands are commonly used for treatment of municipal sewage. The treatment is usually aimed at removal of organics, suspended solids, nutrients and microbial pollution. The information on removal and fate of heavy metals is very limited. The purpose of this study was to evaluate the amount of sediments and heavy metal concentration in the sediments in filtration beds of seven constructed wetlands with horizontal subsurface flow treating municipal sewage with various length of operation. The results revealed that concentrations of Cd, Ni, Pb, Cu, Cr and Zn in the sediment are mostly comparable with concentrations occurred in natural unpolluted or slightly polluted wetlands. The concentrations are much lower than those found in wetlands impacted with mine drainage waters or wastewater from industrial operations. Concentrations of studied heavy metals exceeded only occasionally limits set by the Czech legislation. However, when heavy metal concentrations are evaluated within the filtration material the concentrations are well below the limits set for soils in the Czech Republic. The results also revealed that concentrations of heavy metals in the sediment do not reflect the time of operation probably due to buildup of sediments from suspended solids contained in wastewaters. However, the sediment mass increases during the course of operation and consequently the metal mass increases as well.