Seven methods of preparation of intact native collagen with telopeptides by acid extraction of calf skin have been compared; the hide was first dehaired by original mild enzymatical method using Bacillus licheniformis protease. The noncollagenous proteins and proteoglycans were previously removed by different ways and collagen was extracted by acid solvents and purified by salt precipitation. The dynamic of noncollagen impurities removing was followed by noncollagen proteins and hexuronic acids analysis in extracts. The purity of the resulting collagen was determined by polyacrilamide gel electrophoresis. The gel-forming capacity of the collagen was determined and the suitability of the product for tissue engineering was estimated by cultivation of fibroblasts and cardyomyocytes of new-born rats on collagen gells. All collagens obtained were not cytotoxic and had good gel-forming capacity. The preparation method with noncollagen impurities removing with 0.02 M K2HPO4 and collagen solution with 0.5 M acetic acid and 5 mM EDTA proved to be the best by final yield of the product and cell reaction to it. Hence, the optimal variant of collagen preparation method has been developed. The Russian Federation patent on this method was taken out.