Many applications likehomeland security, radiation protection, control of fissile material proliferation and other require not only detection of radioactive materials, but also their localization. We are presenting a directional detector based on an array of semiconductor detectors capable to determine direction where the radioactive source is placed. Semiconductor single pad detectors are arranged into rows and separated by a shielding material. Selection of the detectors and shielding material depends on the type and energy of the radiation desired to monitor (i.e. X-rays, gammas or neutrons). Level of the signal, i.e. count rate, in each detector depends on the angle of the incoming radiation. Analysis of the count rate in each detector allows calculating angular position of the source. A series of simulations and evaluating measurements of the directional radiation detection principle is presented.