X-ray is ionizing radiation used in several areas such as analytical sciences, medicine and security areas. X-ray machines are used in the entrance of important places (airports, shopping centers, etc.) for security purposes. The aim of this study was the investigation of the potential effects of X-ray irradiation on anti-diabetics (metformin HCl, pioglitazone HCl) and proton pump inhibitors (PPI) (lansoprazole, pantoprazole sesquihydrate) pharmaceuticals which are used in chronic diseases by Electron Spin Resonance (ESR). ESR analysis was done before and after different X-ray irradiation doses. Afterwards, ESR spectra and resonance peaks were evaluated. As a result, no significant free radicals were detected by ESR resonance peaks and also, their ESR intensities did not change significantly by increasing X-ray doses.