pider dragline silk is Nature's high-performance protein fiber. This biomaterial has attracted much interest from scientists in various disciplines since it has become feasible to produce spider silk proteins by means of biotechnology. This article reports on research directed toward the regeneration of spider silk. A procedure is describedincluding spinning and postspinning processingthat produces fibers with promising mechanical properties from dissolved natural spider dragline silk. Tensile tests and structural characterization of the regenerated fibers illustrate correlations between the macroscopic and microscopic properties of the final material and between these properties and the fiber's processing history. Results point to the importance of an aqueous environment in the annealing of structure. The revealed structure−property relationships are expected to be of fundamental importance for the future design of man-made protein products.