Abstract: A mobile X-ray apparatus comprises a base and a column on the base and rotatable about a vertical axis. A carriage is mounted for upward and downward movement on the column and an arm is mounted on the carriage for movement therewith. On one end of the arm is an X-ray tube head assembly which is rotatable with the column about its vertical axis throughout a 180.degree.. The tube head assembly is counterweighted by an X-ray film cassette bin plus control circuitry for operating the X-ray tube, together with the housing for the control circuitry. The tube head assembly may be placed in a storage and transport position in which the tube head is well within the confines of the base of the unit, thereby contributing to the stability of the unit.