Native and nucleated PHB has been melt-spun and the properties of the resulting fibers have been investigated. Biocompatible nucleating agents such as HAP and THY were compared to BN as a reference material. DSC was used to investigate the non-isothermal crystallization kinetics as a function of processing temperature and cooling rate. It was found that particularly the choice of process temperature can ensure sufficient primary crystallization of native PHB: heating not higher than 10-15 K above the melting temperature induced a favorable crystallization behavior of native PHB. Thus, melt spinning at low process temperatures without additives was demonstrated to be the key to the formation of well-defined hollow PHB fibers.