[en] Purpose/Objective: Asymmetric Collimating System in medical linear accelerator is becoming widely used in many radiation centers. A number of approaches has been proposed by many investigators to calculate doses for asymmetric fields in order to account for changes in some dosimetric parameters. However, most of them are applicable to the effective center of the asymmetric beam. The present work has given a generalized approach to calculate dose at any point within the defined asymmetric field. Materials and Methods: Method proposed by Marinello et. al (1992) was adapted to find out the scattering contribution of each jaw which is referred as Asymmetry Factor (AF). AF for each jaw is normalized to a maximum opening of the collimators. Experiments were devised for the 6 MV, 18 MV of Varian CL-2100C and 6 MV of 600C. Measurements were taken in miniphantom and in water phantom using ion chamber dosimetry. A method was developed and tested by comparing its predictions with measurements. Results: AF was found to be affected to a greater extent as the monitor chamber comes closer to the collimators. If the monitor chamber is moved parallel to the closing jaw, AF is almost equal at all chamber positions along that axis and is determined solely by the distance of the chamber to collimator edge. This behavior of these factors was utilized advantageously for dose calculation at any point within the defined field. The agreement between predicted and measured dose rates is within 1.0%-1.5% even in highly asymmetric field for all energies of both machines. Another calculation using AF's shows that the collimator scatter factor (S_c) for symmetric field can be used if the point of calculation is at the center of the asymmetric field and also for points situated at least 6.0 cm from the collimator edge. Otherwise, the error increases as the point gets close to the border of the field. Conclusion: The procedure discussed using AF's gives an accurate dose calculation in all clinical situations both for symmetric and asymmetric fields and confirms that the use of collimator scatter factor (S_c) derived from symmetric fields is accurate enough for most clinical situations