One of the greatest challenges in the attempt to create functional liver tissue in vitro is the maintenance of hepatocyte-specific functions. The pharmaceutical industry has long awaited the development of engineered liver tissue, which could represent a long-term, inducible, high-fidelity model for high-throughput screening of new drug compounds. It is also anticipated that such engineered models could one day be used in liver transplants, where replacement is limited by chronic donor shortages. As isolated hepatocytes dedifferentiate rapidly in culture the use of hepatocytes in long-term studies has proved to be a difficult challenge. Here we report a system of rat hepatocytes cocultured with primary rat hepatic stellate cells on a biodegradable poly(DL-lactic acid) substratum. These coculture conditions were found to encourage the rapid self-organization of three-dimensional spheroids. The spheroids formed exhibit hepatocyte-specific functionality (CYP-450 activity and albumin secretion) after almost 2 months in static culture.