Abstract. Background and Aims: Profiling according to a staging model could be useful for differentiating among the heterogeneous group of treatment-seeking substance use disorder (SUD) patients. The staging model that was evaluated in this study is analogous to the hierarchical Tumor-Nodes-Metastasis (TNM) model in oncology. The proposed model distinguishes profiles derived from the following stages of addiction: (0) addicted, but not severely; (1) severely addicted, but without psychiatric comorbidity or social disintegration; (2) severely addicted with psychiatric comorbidity, but with no social disintegration; and (3) severely addicted in combination with psychiatric comorbidity and social disintegration. Methods: We tested whether subgroups suggested by the staging model for SUDs could be identified among Dutch treatment-seeking SUD patients (N = 6,602). Results: The profile of 5,153 patients (80.9 %) fitted the staging model, and the model was invariant for age, sex, and primary substance of abuse. The majority of the patients not fitting the model (N = 906 of 1,202; 75.4 %) were not severely addicted but were in treatment or had recently been treated for a comorbid psychiatric disorder. When psychiatric treatment was removed as an indicator for the presence of psychiatric comorbidity, the fit increased to 87.1 %. Conclusions: These results support the validity of the hierarchical staging model, which may be used to match patients to specific treatment regimens. Keywords: staging, profiling, disease progression, addiction severity, treatment-seeking patients, substance-use disorders