Isotactic polypropylene-block-polyethylene (iPP-b-PE) block copolymers are a very intriguing class of crystalline-crystalline block copolymers. The morphology and the crystallization behavior of crystalline and double crystalline block copolymers containing stereoregular polyolefin blocks have been the subject of a small number of studies to date, due to the intrinsic limitations of the living polymerization methods. These materials are characterized by a wide range of morphologies since the solid-state structure can be governed or by the microphases derived by the melts immiscibility or by the crystallization of one or both blocks. In this work iPP-b-PE samples with well-defined molecular architecture (block lengths, molecular mass and molecular mass distribution) have been synthetized by using living Cs-symmetric pyridylamidohafnium dimethyl precatalyst. In the melt state, rheological and calorimetric studies have been conducted. A calorimetric analysis has been previously made to identify the temperature range for the rheological tests. Frequency sweep tests have been completed on some specific iPP-b-PE samples at various temperatures, to verify the TTS principle and build up the master curves of the block copolymers. The horizontal shift factor has been evaluated at various temperatures for iPP-b-PE samples. Transient tests (creep and relaxation experiments) have also been used to characterize the “long time” rheological response. In particular, the stress relaxation modulus and the compliance have been converted into the corresponding viscoelastic moduli to enlarge the frequency window. At low frequencies, the experimental scaling of G’ has been assessed, with a different power law of G’ vs frequency. By comparing the experimental evidence of this work with the existing literature on diblock copolymers, it has been possible to recognize various ordered mesophases and to relate them to the molecular coompisition of the block copolymers.