The annual worldwide production of polymeric materials to 1996 was around 150 million ton, with per capita average consumption of plastics in the developed countries of 80-100 k/year, for example, in China was estimated plastics residue in 16 million ton in 2000, being the fifth country in the world responsible for this residue, after U.S., Japan, Germany and South Korea. Consumption per capita in countries as Colombia is low due to limited production and use of these materials for consumer habits [1]. In Colombia to 2002 almost 4 million tons of solid residue was produced [2], Medellin generated 58.572 ton/year of plastics [3]. Dow Polyurethane estimated that in 1999 the global consumption of polyurethanes was approximately 6.8 million ton. Europe and North America are regions with the highest production [4]. In Colombia the polyurethane demand has increased over the past three years, from 1.000 ton in 2003 to 2000 ton in the year 2005 and the projections in the market continues increase, these datas do not include the polyurethane that produced inside country by reacting a polyol whit a polyisocyanate [5]. Techniques more used to treat solid residue polymer are recycling, composting, incineration and landfill [1]. Research on the pyrolysis of polyurethanes conclude that polyaromatic compounds occur and free radicals that can be contained and retained [6], It can produce compounds such as isocyanates that cause problems to health and the environment [7]. Physical properties of this polymer is that it is thermostable,and it can not recycled again [8]. One way to minimize this residue, either before or after its disposal in landfill, would resort to bioremediation (biorecuperation) [9][10][11], which is a treatment for the decontamination and restoration of water, gases and soil. It is used to describe a wide variety of engineering systems that use microorganisms to degrade organic chemicals (biological treatment). The bioremediation process is a comprehensive and global, where the biodegradation is the biological reaction that takes place, this being the transformation of the contaminant through metabolic processes [12][13]. This would be applicable in cases where no provision has been made use of residue plastics for recycling or other process, and would also reduce the total volume of solid waste are ready, which would increase the lifespan of the landfill where it is providing this residue [14]. Polyurethane, in spite of its synthetic origin, is likely to be biodegraded by microorganisms in a natural way. Enzymatic attacks can occur on polyurethanes by hydrolases such as urease, proteases and esterases. Indeed, proteolytic enzymes (papain and urease) and cholesterol esterase were used to degrade polyurethanes in vitro [15]. Biodegradation of residual polyurethane by means of Aspergillus niger was evaluated. Respirometric tests were performed using an OXITOP equipment, tests which showed a 98% of consumed oxygen in a 200 hours lapse. Biodegradation was done in an aerated accumulation reactor, at 40% humidity and 25 ºC temperature during 45 days. Spectroscopy IR analysis showed a 610 cm-1 band, which corresponds to aromatic rings that were released when the amide II and IV links were broken. Scanning Electronic Microscopy (SEM) showed changes in the polyurethane surface. It is recommended to continue this study using a mixture of microorganisms and longer exposure time, to achieve a degradation that allows the carbon and nitrogen present in the waste, is available as back land for agriculture, making the toxicity studies required plants. [ABSTRACT FROM AUTHOR]