Purpose: The prognostic effect of isolated infradiaphragmatic involvement in Hodgkin lymphoma (HL) is controversial, and there are little data about patients treated with current therapies. Therefore, we performed a risk factor analysis to focus on isolated nodal infradiaphragmatic disease in patients treated within the German Hodgkin Study Group trials HD13 (clinical trial information: ISRCTN63474366) and HD14 (clinical trial information: ISRCTN04761296) for early-stage HL. Patients and Methods: Characteristics and outcomes of patients who had infradiaphragmatic HL were compared with patients who had supradiaphragmatic disease. Progression-free survival (PFS) and overall survival (OS) were estimated according to Kaplan-Meier methods and were compared between groups using the log-rank test and Cox proportional hazards regression, which was also applied for multivariable analyses that adjusted for relevant baseline characteristics. Results: Of 2,903 qualified patients, 223 (7.7%) were diagnosed with isolated nodal infradiaphragmatic disease. In general, these patients were older, had a poorer performance status, were more often male, and had the nodular sclerosis subtype less often than those with supradiaphragmatic disease. After a median follow-up time of 51 months, PFS and OS were significantly worse in patients with infradiaphragmatic disease (5-year PFS and OS, 80.1% and 91.5% v 91.2% and 97.6% in patients with supradiaphragmatic disease; each P, .001). In multivariable analyses, infradiaphragmatic HL remained a significant risk factor in terms of PFS (hazard ratio [HR], 1.5; 95% CI, 1.04 to 2.2; P = .03) and OS (HR, 2.0; 95% CI, 1.2 to 3.5; P = .01). However, inferior PFS and OS could not be observed among those patients treated with the more intensive chemotherapy (two cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine [ABVD] in HD13, and two cycles of escalated bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone [BEACOPPescalated] plus two cycles of ABVD in HD14; all patients received 30 Gy of involved-field radiotherapy). Conclusion: Early-stage HL that presents with infradiaphragmatic disease only represents a distinct patient group with an inferior outcome. However, this adverse outcome can be outweighed by appropriate combined modality treatment.