The monthly variation of selenium concentration in atmospheric particulate material of Ankara was investigated. The selenium concentrations in possible pollution source materials like coal, fuel oil and their bottom and fly ashes were determined to obtain the percent transference of selenium into the atmosphere. Instrumental thermal neutron activation analysis and atomic absorption spectroscopy were applied for the analysis of selenium in the samples. Selenium enrichment factors with respect to the fuels, soil of Ankara and crustal material were also calculated. Atmospheric selenium concentration is found to increase during winter months and the main cause of this increase is the emission of selenium into the atmosphere due to fuel combustion.