The first step in using photovoltaic and solar thermal plants is the study of the direct radiation on a normal surface, Hbn, and the choice of the right tilt angle, s, for its panels. Solutions depend on whether the panels are fixed (s remains constant) or are mobile (biaxially or uniaxially follow the sun, change of tilt several times a year). However, whatever the chosen position, this requires to have available the measured data of Hbn in the considered site. Ouarzazate region will accommodate the first large integrated solar project plants (500 MW) for electricity production on a large scale. As, Hbn is a very important component for concentrating systems and for the estimation of the radiation received by titled surfaces, we have been studying its characteristics. On the other hand, the sunshine duration is being measured in Ouarzazate station since 1957 and with the absence of Hbn, we determined a relationship between direct radiation and sunshine duration. This correlation allows us to compute the direct radiation from sunshine records with the same climatic conditions. Looking forward to have available the direct radiation records in order to compare them with the estimated ones to check if the statistical characteristics of Hbn are faithfully reproduced. So, the results obtained should be improved as far as the stochastic characteristics of Hbn, is concerned. Although, the considered correlation has been established for Ouarzazate, this relation could be extended to other areas in the country, with some corrections. Key words: Direct radiation, estimation, stochastic, photovoltaic, concentrated Thermo-Solar, electricity.