Since their discovery in 90-ties last century, the multiwall carbon nanotubes (MWCNT) found many applications in different fields. Thanks to their excellent mechanical properties MWCNT are lately of special interest in the preparation of reinforced biodegradable composites with specific biomedical applications where resistant but still bio-resorbable materials are indispensable. Even though some groups reported already the effect of MWCNT on cellular metabolism in different systems, still remains unclear whether MWCNT could have some beneficial role on bone cells. Recently it has been reported by the others that poly(l-lactide) (PLLA):MWCNT composite inhibits fibroblast proliferation in vitro [1]. Here we demonstrate in more details the effect of PLLA:MWCNT composite on cell adhesion, proliferation and differentiation with a specific respect to bone cells.