We demonstrate that x-ray absorption spectroscopy ͑XAS͒ can be used as an unconventional characterization technique to determine the proportions of different crystal phases in polymorphic samples. As an example, we show that ratios of anatase and rutile phases contained in the TiO 2 samples obtained by XAS are in agreement with conventional x-ray diffraction ͑XRD͒ measurements to within a few percent. We suggest that XAS measurement is a useful and reliable technique that can be applied to study the phase composition of highly disordered or nanoparticle polymorphic materials, where traditional XRD technique might be difficult.