After careful examination of the literature we propose the following mechanism (Scheme 5a): after coordination of the platinum to the cyclopropene double bond (complex I), ring-opening occurs with the formation of vinyl platinum carbene species II (Path A). Such sequence appears to be highly probable due to the π-philicity of platinum complexes. However, an oxidative addition of the platinum complex onto the C-C bond, followed by cycloreversion of metallacyclobutane intermediate III (Path B), resulting in the same metal carbene intermediate II cannot be excluded at this stage. Carbene II then undergoes pericyclic [1,5] -σ-bond rearrangement, resulting in platinum hydride intermediate IV. Intermediate IV finally leads to the product and regenerates the catalyst through reductive elimination. To further support the proposed catalytic cycle, we performed isotope labeling studies. Deuterated cyclopropene 5 was prepared in 6 steps from d -acetone (see for the preparation) and subjected to the reaction conditions. To our delight, the deuterated product 6 was formed selectively, providing strong support for the proposed mechanism. To the best of our knowledge such pericyclic [1,5]-σ-bond rearrangement is a unique feature of vinyl platinum carbenes, which has not yet been reported with other transition metal complexes. In summary, a protocol for the Pt-catalyzed isomerization of cyclopropenes to 1,3-dienes is reported. The transformation resulted in the formation of highly substituted 1,3-dienyl carbinols. The utility of the products was demonstrated by two distinct Diels-Alder cycloadditions. Isotope labeling studies supported the formation of a Pt-carbene intermediate, which underwent [1,5]-hydride shift. So far this rearrangement was only reported as a minor and undesired pathway in Pt-catalyzed transformations. We hope, that our work will attract more attention to this unique elementary step, which can be used in the development of diverse synthetic transformations.