Epitaxial thin films of (100) CrO₂ were fabricated by chemical vapor deposition (CVD) at atmospheric oxygen pressure onto (100) TiO₂ single-crystal substrates. The films were 20, 60, 66, 80, 150, and 161 nm in thickness. Ferromagnetic Resonance (FMR) measurements were performed at X- band (9.5 GHz) at room temperature for all samples. Angular dependencies of FMR spectra in both "in-plane" and "out-of-plane" geometries were measured. The directions of easy and hard axes of magnetization were determined from "in-plane" measurements, when the DC magnetic field was rotated in the film plane. The orientation of crystallographic axes in the film plane was controlled by the X-ray measurements. In the "out-of-plane" measurements, the DC magnetic field was rotated from that at room temperature the minimal FMR resonance field (i.e. "easy axis" of magnetization) in all films is achieved in the direction of DC magnetic field parallel to the "c" axis of CrO₂ rutile structure. Splitting (or asymmetric lineshape) of FMR response due to the surface and bulk modes was observed. This indicates an essential surface pinning of magnetization at interfaces of CrO₂ films. A shift of FMR signal to the lower magnetic fields in the normal direction reflecting an increase of the anisotropy field was observed upon decrease of the film thickness. The values of the room temperature magnetization and anisotropy fields were also estimated from the FMR measurements. LRT thanks UR.01.01.061 and NIOKR/ANT 06-6.2-47/2001(F) for partial support.