The predetermination of the runoff in the non gauged basins constitutes the objective of numerous researches because of a lack of data covering them. Thus, the use of mathematical models became the suitable approach. Runoffs at the exit of basins, in addition to being influenced logically by rainfalls and their intensities, they are under the influence of other factors which condition the surface discharge such as the physiographical parameters of the basins, lithology, vegetation cover and evaporation. The aim of this work is to seek statistical relations which bind runoff observed at the exit of basins to rainfalls and some physiographical factors for basins of Algeria between September 1985 and September 1993. The simple and multiple correlations carried out on 23 basins made it possible to emphasize that some physiographicalcharacteristics are explanatory of the variance of the runoff to significant thresholds.