PURPOSE: Although several studies provide data on reference dosimetry, ionization chambers are in clinical use worldwide, for which no or only a few correction factors for beam quality are available. The aim of this study was to calculate beam quality correction factors in electron and photon fields for four cylindrical ionization chamber, i.e. CC08, CC04, Razor™ Chamber and Razor™ Nano Chamber (all IBA, Dosimetry, Schwarzenbruck, Germany). METHOD: Monte Carlo simulations were performed with the EGSnrc code system to calculate the beam quality correction factor k RESULTS: k CONCLUSION: Electron and photon beam quality correction factors k