X-ray excited optical luminescence (XEOL) and X-ray absorption near-edge structure (XANES) have been used to identify the origin of luminescence from chemical vapor deposited (CVD) diamond films. The XANES data provide direct evidence that luminescence from the CVD diamond films originates from the diamond phase, whereas both the sp(2)- and H-bonded carbon, which are always present in the CVD diamond films, contribute little to the overall luminescence. This observation contradicts a previously proposed model, in which broad-band emissions from CVD diamond thin films are assigned to sp(2) carbon impurities and incorporated hydrogen in the film.