Poly(EthyleneOxideTerephthalate)/Poly(ButyleneTerephthalate) (PEOT/PBT) segmented block copolymers are widely used for the manufacturing of 3D-printed bio-scaffolds. In this work we study the rheology of a commercial PEOT/PBT sample both in the melt state and during the thermally-induced sol/gel transition. On the one hand, non-isothermal viscoelastic measurements under oscillatory shear flow are performed at high temperatures to assess the material processability in the melt state. On the other hand, both non-isothermal and isothermal experiments across the order-to-disorder transition are used to determine the temperature dependence of the phase transition, which is a relevant factor in determining the characteristics of the printed bio-scaffolds. The effect of additional components, such as bio-active nanoparticles, on the phase transition kinetics and on the rheological response is also considered. The importance of the rheological characterization when designing the 3D-printing scaffold process is presented and discussed.