Complex gel materials of Type I collagen and aluminosilicate containing imogolite nanofibers were prepared as opaque gel by mixing an acidic fine dispersion of aluminosilicate with an acidic solution of collagen. The product was stained blue by Coomassie Brilliant Blue (CBB), indicating that the gel contained collagen. A white sponge was obtained after lyophilization of the complex gel. Elemental analysis revealed that the complex contains C, H, N, Al, and Si atoms; and the compositional ratio of aluminosilicate/collagen (w/w) was calculated as 0.75 for the complex gel when aluminosilicate was mixed with an equal quantity of collagen. Transmission electron microscope (TEM) observation showed that aluminosilicate nanofibers were homogeneously distributed in the collagen matrix. The thermogravimetric analysis (TGA) curve of the complex was not a simple summation of each components, and especially, the weight loss step corresponding to detachment of the adsorbed water observed in aluminosilicate became difficult to distinguish, suggesting that the adsorbed water was removed in the complexation. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 2284-2290, 2010