Background : After orchiectomy in stage I seminoma the standard is adjuvant radiation therapy. We analyzed the patients retrospectively to evaluate the contributions of the treatment volume and dosage to treatment outcomes. Materials and Methods : Between January 1999 and December 2005, 91 stage I seminoma patients with a median age 36 (range;22-62) applied to our center, who were treated using anterior-posterior parallel opposed fields with linear accelerator or Co60 after orchiectomy. Twenty-five (27.5) patients received irradiation to the paraaortic and ipsilateral pelvic nodes, and 66 (62.5) patients only received to paraaortic nodes. Results : With a follow up time of median 57 months (range; 27-104), paraaortic nodes treated group had 4 relapses (6) - 3 of them pelvic, one of them both pelvic and paraaortic. Both paraaortic and ipsilateral nodes irradiated patients had only one relapse (4) (P = 0.726). While the 5 year overall survival (OS) is 98.8, it is 100 in the dog-leg group and 98.4 in the paraaortic group (P = 0.548). Univariate analyses of OS and Disease Free Survival (DFS) showed that there is no statistically significant difference related to factors as age, histologic subgroup, tumor size, rete testis involvement, radiotherapy (RT) fields, dose ranges and the therapy device. Conclusion : Adjuvant RT approach is the preferred for non-compliant low risk patients as well as intermediate and high risk patient in stage I seminoma. 20 Gy/ 10 fractions/ 2 weeks RT is the adequate treatment.