Abstract: We have constructed a bioreactor aimed at imitating the three-dimensional micro- and macroenviron-ment of the liver. In vivo hepatocytes are arranged in plates of cell monolayers and are specifically attached with both sinusoidal surfaces to the space of Disse which contains extracellular matrix. Nonparenchymal cells are located on the other side of the space of Disse toward the sinusoid. For supporting monolayer hepatocytes with bipolar attachment to the extracellular matrix, we used a double gel culture technique that sandwiches hepatocytes between two layers of collagen. In double gel cultures, albumin production increases during an adaptive period to the in vitro environment. In contrast to conventional trol (4). We have studied a variety of cellular parameters such as cytochrome P450 3A expression (27), drug metabolism (27, 28), protein secretion, and morphology. In situ-like morphology and stable function was obtained in DG culture.