Effective clinical management of substance use disorders involves accurately identifying patients, monitoring of clinical outcomes, and risk stratifying of patients. This chapter provides a review of standardized questionnaires and screening tools essential for addiction-focused treatment. We examine a number of instruments that are helpful to identify patients with at-risk alcohol or other substance use disorders using validated instruments such as the AUDIT-C, TAPS, and ASSIST. This chapter also offers specialized guidance on risk stratification for diverse and vulnerable populations including adolescents, older adults, and pregnant patients. Furthermore, the text reviews instruments that are helpful in the management of patients being considered for or receiving chronic opioid therapy including the ORT and COMM. We also review standardized questionnaires used in the management and assessment of both alcohol and opioid withdrawal along with more recently developed tools for the hospital setting. As measurement-based care is increasingly being used in substance use disorder treatment, the chapter reviews instruments used to monitor addiction severity over time. Through this review of standardized questionnaires, this chapter serves as a resource for implementing systematic, data-driven screening and monitoring in clinical practice.