The artificial lightweight aggregate (ALA) was fabricated using a sewage sludge produced from a municipal wastewater, and impact sound reduction analysis for concrete slab made with the ALA was done. Specific gravity of ALA decreased with the sewage sludge content due to the gas bloating caused by melt films on the surface of ALA, which is formed easily because of low temperature melting P2O5 and modifiers, CaO, MgO and K2O contained in the sewage sludge. And water absorption of ALA increased with the sewage sludge content owing to open pores which were formed by connecting an inside pore to a surface. A specific gravity of 10mm diameter ALA was lower than that of 7mm ALA since a trapped gas could not escape from the core to the surface of ALA due to longer moving distance. The ALA containing 20 wt% sludge sintered in a electric furnace showed a specific gravity 15% lower and water absorption 50% higher than that of ALA sintered in a rotary kiln. It might be attributed to easy release of gases during the pre-heat zone (600-1000oC) in the rotary kiln, resulting in densification of ALA. Light and heavy weight floor impact sound of concrete slab made with ALA were 63-72dB and 44-76dB respectively, similar to a general concrete slab. The unit weight of concrete slab made with ALA, however, was 18% lower than that of general one owing to the lightweight of ALA, so it could be suitable to applying for high-rise building.