Objective: Determination of the most appropriate planning technique implementing maximum dose to target organs; minimum dose to critical organs as rectum, urinary bladder and femoral heads using different plans in three dimensional conformal radiotherapy (3D-CRT) of prostate cancer. Material and Methods: Eighteen distinctive conformal plans were made in each of 17 cases (radical RT for nine and adjuvant RT for eight) selected patients with prostate cancer who applied to Ego University Department of Therapeutic Radiation and Oncology. Values of rectum V50, V80, V90, bladder V90, femoral heads (V70 for radical, V80 for adjuvant) were evaluated using cumulative dose-volume histograms, and the level of statistical significance was assessed with t-test and one-way variance analysis after mean values and standard deviations of 1530 data, for five values of 18 plans of 17 patients, had been calculated. Results: When 18 distinctive planning techniques were compared, of the 3-field techniques, at "0 degrees,90 degrees" plan minimum dose values were detected for rectum and maximum dose values were detected for femoral head (F>3.25, p<0.05). A significant difference was not found for urinary bladder values. In the 4-field techniques, maximum dose for rectum was obtained at "45 degrees,135 degrees" plan, minimum values for femoral head were obtained at box technique and "45 degrees,135 degrees" plan (F>4.54, p<0.05). In 5-field techniques, "0 degrees,72 degrees,144 degrees" plan was found significantly high in terms of rectum V90 and V80 values in operated subjects and rectum V80 and V50 values in the subjects not operated (F>3.58, p<0.05). When 6 and 7-field planning techniques were compared between themselves, a significant difference was not found in terms of rectum, urinary bladder and femoral head doses. Conclusion: It was concluded that box technique would be more appropriate for the initial phase of both radical and adjuvant 3D-CRT of prostate cancer and double-weighted 6-field "45 degrees, 90 degrees, 135 degrees" technique for boost therapy.