The rotational spectrum of the CrF radical in the X (6) Sigma(+) state was observed by employing a source modulation microwave spectrometer. The CrF radical was generated in a free space cell by a de glow discharge in CF4 and He. The chromium atom was supplied by the sputtering reaction from chromium powder placed over a lower surface of the cylindrical electrodes. The transitions with N=12-11 to 20-19 were measured in the region between 270 and 460 GHz. The rotational, centrifugal distortion and several fine-structure constants were obtained by a least squares analysis.