The degree of collagen fibril formation was altered by varying the preservation conditions. The collagen substrate under atmosphere of nitrogen gas for 4 days exhibited well-developed collagen fibril network accompanied with the frequency of round-shaped chondrocyte cells (f(R)) of 0.62, the value of which was slightly lower than that on the reference substrate. The exposure to air and prolongation of preservation led to further degradation of collagen fibril networks accompanied with f(R) lower than 0.4. It was thus demonstrated that the preservation conditions of the collagen substrate influenced the chondrocyte cell morphology. (C) 2012, The Society for Biotechnology, Japan. All rights reserved.