PURPOSE: Adjuvant radiation therapy (ART) for stage I seminoma can cause adverse late effects and alternative postorchiectomy management strategies have been developed. This study evaluated ART trends in the United States and the impact of clinical and sociodemographic factors on ART recommendations. METHODS: Of men diagnosed with stage I seminoma from 1990 through 2004, 3,125 were identified using the Surveillance, Epidemiology, and End Results cancer registry. A multivariable logistic regression analysis was performed to assess whether there was a significant association between diagnosis year, diagnosis age, race, county education level, region, tumor size, tumor category, and the recommendation for ART. RESULTS: There was a significant association (P < .001) between later year of diagnosis and a decrease in ART recommendation. Compared with men diagnosed in 1990 to 1994, men diagnosed in 1995 to 1999, and 2000 to 2004 were less likely to have ART (adjusted odds ratio [OR], 0.63; 95% CI, 0.48 to 0.84; and OR, 0.49; 95% CI, 0.37 to 0.63, respectively). There also was a significant association (P < .001) between county education level and ART recommendation. Men residing in counties with the highest education level were more likely to receive ART than men residing in counties with the lowest education level (OR, 2.12; 95% CI, 1.59 to 2.82). Also, men older than 30 years were more likely to receive ART than men age 30 or younger (OR, 1.26; 95% CI, 1.03 to 1.55). CONCLUSION: ART recommendations for stage I seminoma are declining. Men in less educated regions and the youngest men were less likely to receive a recommendation for ART.