Modern, high energy X-ray therapy units are sources of undersired neutron radiation from (gamma, n) and e, e'n) reactions taking place in the bremsstrahlung target, flattening filters, shielding materials and collimators inside the treatment head. The photoneutrons from the primary source in the accelerator head are transported and scattered inside the entire structure of the machine and the treatment room and contribute to the total dose delivered to the patient during the radiotherapy course. Measurements of neutron radiation around the 16-50 MV photon beams from medical electron accelerators in Sweden (16, 18 MV Philips, 18 MV Saturne, 21 MV Microtron, 42 MV Siemens betatron, 50 MV Racetrack microtron) were performed using passive and active detection techniques with an indium foil activation and a ²³⁵U fission chamber, respectively. The highest neutron production per unit photon dose in the patient is about 2.5 x 10⁷ n cm^-2 Gy^-1 and occurs for 18-21 MV treatment units. At high photon energies (40-50 MeV), the neutron production is lower and in the range (0.6-1.8)x10⁷ n cm^-2 Gy^-1. The level of neutron radiation around different treatment units operating with the same maximum electron energy varies due to differences in the construction of the treatment head and the design of the treatment room.