Germ cell tumor (GCT) progression typically occurs in a predictable sequence of disease spread to the retroperitoneum first and then distant metastases. Understanding the role of serum tumor markers at various disease stages is critical for guideline-concordant management and to optimize patient outcomes, avoiding both undertreatment and overtreatment. For patients with seminoma, retroperitoneal lymph node dissection now represents an option for patients with low volume retroperitoneal lymph node disease, with the goal of avoiding the long-term toxicities associated with chemotherapy and radiotherapy. For patients with residual postchemotherapy masses in seminoma, increasing evidence suggests that PET scans should be utilized/interpreted with caution, and that in the absence of mass growth continued follow-up may be the strategy for most patients. Similarly, for patients with nonseminomatous GCTs (NSGCT) and equivocal retroperitoneal lymph nodes at presentation, re-scanning after an interval of approximately 6-8 weeks may be preferable to initial treatment, as many of these nodes represent benign processes and as such will resolve. Nevertheless, postchemotherapy retroperitoneal lymph node dissection remains a critical component of the management of patients with NSCGT and a residual mass.