The purpose of the research was to produce nanofiber-modified paper with enhanced strength. The materials used in the research were cotton-comber pulp and a composite of PLA (polylactic acid) and PHB (polyhydroxybutyrate) nanofibers. Two sets of test sheets were formed: from the pure cotton-comber pulp and from the cotton-comber pulp with 5.5% of ground nanofibers. A range of strength tests showed a significant strength improvement (an increase in breaking length of 17%). The thesis was confirmed and the results encourage further research into the subject matter of this article.