Nowadays as a result of the increasing environmental friendly consciousness and the decreasing oil reserves, natural origin based materials are developed. These materials are not only based on renewable, natural resources, but capable of biodegradation in compost. These biodegradable polymers (biopolymers) can be inserted into the nature’s recycling process. One of the most important biopolymers is starch. Starch can be processed like a thermoplastic material by adding plasticizers, creating the so called thermoplastic starch. However the price of starch is rather low, it has certain drawbacks retarding its wide industrial usage. It is sensitive to moisture, disrupts in pure water, has low mechanical properties, and in time it ages. This ageing or time-dependent behavior was analyzed with injection molded tensile specimens. The shrinkage and mechanical properties of the specimens were determined as a function of ageing time. The fracture surface was analyzed by scanning electron microscope. The results of the measurements were compared with previous examinations.