The first measurement of the W-boson helicity in top quark events with the 2010 data of the CMS detector will be presented. The W-boson helicity is an interesting field of study since it can indicate physics phenomena beyond the Standard Model. In the Standard Model it is predicted that the W-boson has two helicity states, the longitudinal and left-handed. The right-handed helicity is restricted due to the V-A structure of the weak interaction. Any deviation observed in the helicity fractions would indicate that the weak charged current interaction, responsible for the decay of the top quark, is influenced by new physics phenomena.