Although clinical stage I (CS I) testicular cancer is highly curable, the optimal management is controversial. The aims of the Swedish and Norwegian Testicular Cancer Group (SWENOTECA) studies for CS I non-seminoma (NS) and seminoma (S) have been to reduce treatment intensity while maintaining high survival rates, reduce the number of patients needing salvage treatment and implement patient autonomy with regard to adjuvant treatment. During 1998-2010 NS CSI patients with lymphovascular invasion (LVI) of the primary tumor (high risk) were recommended bleomycin, etoposide, cisplatin (BEP) × 1. During 2000-2006 S CS I patients had the option to choose surveillance or adjuvant radiotherapy (AR). In 2004, carboplatin × 1 (AUC7) was added as a third treatment option. In 2007 a new risk-adapted treatment protocol for S CS I was initiated. Patients with two risk factors (tumor size > 4 cm, tumor growth in the rete testis) were recommended carboplatin × 1 and patients with 0-1 risk factor were recommended surveillance. All patients were provided with oral and written information of possible management options and could choose the other alternative. The relapse rate for NS CS I with BEP × 1 was 3.2% for high risk, and 1.6% for low-risk patients. Five-year cause-specific survival was 100%. For S CS I-patients treated before 2007, 14.3% on surveillance relapsed, 3.9% after carboplatin, and 0.8% after AR. Five-year cause-specific survival was 99.9%. For S CS I-patients treated from 2007, a relapse rate <3% was confirmed for patients without risk factors. SWENOTECA considers BEP × 1 standard adjuvant treatment in NS CS I high-risk patients. Low-risk patients should have the opportunity to receive BEP × 1 following thorough information regarding pros and cons. For S CS I patients without risk factors, adjuvant treatment is not necessary. For patients with risk factors, patient autonomy should be respected.