In this article, we report the effects of the molecular weight on the electrospinnability of polylactide (PLA) solutions under identical conditions. Only above the entanglement concentration could uniform fibers be generated for PLA with a low molecular weight. However, electrospinning from a solution below its entanglement concentration produced uniform nanofibers when a high-molecular-weight PLA was adopted. The slow relaxation of high-molecular-weight PLA was expected to preserve chain interconnectivity in the highly stretched liquid jets during electrospinning. Correspondingly, rapid cold crystallization and a high modulus were exhibited by the resulting PLA nanofibers because of their remarkable molecular alignment. (C) 2017 Wiley Periodicals, Inc.