The series of polyurethane – carbon nanofiber (PU/CNF) elastomers was prepared and characterized. Polyurethane elastomeric matrix was made from polybutadiene-based macrodiol of MW ca. 2000, 1,6-diisocyanatohexane, and butane-1,4-diol. Carbon nanofibers (up to 2.25 wt.%) were dispersed in the mixture of monomers, i.e., before polyurethane formation. The influence of the nanofiber concentration on functional properties was studied by the series of microscopic, thermal, mechanical and electrical techniques of analysis. The best functional properties has PU/CNF composite containing 0.75 wt.% of CNF.