The thickness dependence of the static and dynamic properties of Co2MnSi (CMS) full Heusler was investigated. Five samples with thickness ranging from 7 to 100 nm were deposited by rf magnetron sputtering on single crystal MgO(001). X-ray diffraction and transmission electron microscopy (TEM) evidence the epitaxial growth of samples, with an epitaxial relationship MgO(001)//CMS(011). Magnetic properties were studied by standard magnetometry and broadband stripline ferromagnetic resonance (FMR). We observe a four-fold magnetocrystalline anisotropy Kc = 1.5 × 105 erg/cm3 for thicker samples, and an increase of Kc up to 2.6 × 105 erg/cm3 for the thinnest sample, accompanied by an increase of saturation magnetization. We attribute this behavior to interfacial effect (strain or stoichiometry).