In the development of new materials, apart from the properties of the materials, the economic and ecological aspects are also of considerable importance. Traditional products whose manufacture requires expensive raw materials are being replaced with composite materials with alternative properties which display better qualities and perform in a better way. Composite materials are obtained from much cheaper components and possess significantly lower relative weight. Over the last few years different kinds of waste materials have been successfully utilized as filler in polymer composites with various applications. This not only reduces the production costs but also offers an opportunity for utilization of waste materials thereby reducing environmental pollution. Among them a large number of insulation composite materials with different practical application have been developed. Many of the composites are thermal, electrical or noise insulating materials based on thermosetting polymers (polyester and epoxy resins) which combine the required physical characteristics with good processing properties. For example polyester resins have a series of valuable properties suitable viscosity, ability to solidify at both room and high temperatures, high electric strength and dielectric ratings, high chemical stability and etc. Experimental research shows that the properties of the composites in this case are a function of both the curing degree of the polymer and the kind and properties of the filler. At the same time there are organic or inorganic waste materials generated by the industrial processes or human activity, which could successfully replace or at least reduce the amount of raw materials used as components in insulation materials. This chapter presents the outcomes of the experimental work aimed to evaluate the possibility for utilization of organic and inorganic industrial waste as fillers in polymer composites with thermaland electrical insulation and sound damping properties.