Abstract: In the Standard Model (SM), the W boson which is a spin 1 particle contains 3 different helicity states. According to the model prediction, a maximum fraction of W bosons which is about 70%, appear to be longitudinally polarized. Another 30% of the W bosons exhibit a left handed helicity state while right handed W bosons are suppressed. Measurement of these various helicity fractions is of great importance within the CMS collaboration since it could provide a way to test experimentally the SM. Here, we study the W polarization measurement using dileptonic ttbar events. In this talk, a status report on the studies which have been performed on this topic is given.