A process for the production of a lignin based polyurethane products is provided. The process comprises mixing at least one dried lignin and at least one isocyanate to form a lignin-isocyanate mixture, and submitting the lignin-isocyanate mixture to a polymerization reaction. The polymerization reaction may include heating the lignin-isocyanate mixture, adding at least one catalyst to the lignin-isocyanate mixture, or mixing the lignin-isocyanate mixture with a resin comprising at least one polyol, in the presence of at least one catalyst. The lignin based polyurethane products obtained by the process may be rigid foams, flexible foams, rigid boards, rigid blocks, coatings, packagings, adhesives, binders, sealants, elastomers, Thermoplastic Polyurethanes or Reaction Injection Moldings. There is also provided a mixture comprising at least one dried lignin and at least one isocyanate for use in the production of a lignin based polyurethane products.