The activities of 226Ra, 232Th and 40K radionuclides have been measured in marble chips, sand, hard rock and cement samples using gamma ray spectroscopy. Radium equivalent activities and external hazard indices have been calculated. These results indicate that all of the materials investigated in this work, except marble chips from Amman, are acceptable for use as construction materials according to the criterion proposed by OECD countries. For some samples of marble chips from Amman, the external hazard index is found to be greater than unity. This should not pose any health hazard if it constitutes a smaller fraction of the construction materials.