An aerobic, endospore forming thermophilic microorganism was isolated from a soil sample in Jordan. The cells stained Gram-positive and the cylindrical spores are terminal and wider than the mother cell. Growth occurs at temperature values between 45 °C and 70 °C, with an optimum at 55°C. The optimum pH for growth is 7.0. The G + C content of the DNA is 50.4 mol% and the sequence analysis of the 16S rDNA shows that the new isolate is phylogenetically closely related to the members of the Bacillus rRNA Group 5. DNA-DNA hybridization studies revealed a high similarity between the new isolate and the thermophilic species of the above mentioned group. A number of thermophilic Bacillus species are combined on the basis of DNA-DNA hybridization data.