Clinical stage I represents the most frequent presentation of both seminoma and nonseminoma testicular cancer. Despite a survival rate of close to 100%, the management of patients with this disease stage is controversial. The recurrence rate is 10% to 20% for patients with stage I seminoma and 15% to 50% for those with stage I nonseminoma. A highly sensitive and specific biomarker of relapse that is applicable to both seminoma and nonseminoma, and able to drive a definitive risk-adapted management of the patients, still is not available. Lymphovascular invasion (LVI) in the orchiectomy specimen has been used as a risk factor in patients with stage I nonseminoma. However, with a risk of recurrence of 50% for LVI-positive patients and 15% for LVI-negative patients, the discriminative power of LVI is modest at best. Various management options exist. In the absence of a predictive biomarker for recurrence, active surveillance avoids overtreatment in 50% to 85% of patients, with no risk of long-term side effects in nonrelapsing patients and a preserved overall survival of almost 100% after specific treatment for recurrent disease. However, although active surveillance has been accepted as the preferred option for stage I seminoma and low-risk stage I nonseminoma, its role in high-risk stage I nonseminoma remains controversial.