Accurate assessment is essential to implementing effective mental health treatment; however, little research has explored child clinicians' assessment practices in applied settings. The current study thus examines practitioners' use of evidence-based assessment (EBA) instruments (i.e., self-report measures and structured interviews), specificity of identified diagnoses (i.e., use of specific diagnostic labels vs. nonstandardized labels, not otherwise specified [NOS] diagnoses, and adjustment disorder diagnoses), and documentation of Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev., DSM-IV-TR, American Psychiatric Association, 2000) criteria. Use of these practices was evaluated via analysis of documentation contained within a regional medical center's medical records. This analysis was limited to 2,499 session notes from patient appointments associated with psychiatric disorders newly diagnosed during 2013. In total, session notes were linked to 694 children aged 7 to 17. Results indicated that EBA use was low overall, although self-report measures were utilized relatively frequently versus structured interviews. Diagnostic specificity was also low overall and clinicians rarely documented full diagnostic criteria; however, EBA use was associated with increased diagnostic specificity. Further, clinicians practicing in psychological, psychiatric, and primary care settings were more likely to use self-report measures as compared to those practicing in an integrated behavioral health social work setting. In addition, structured interviews were most likely to be utilized by clinicians practicing in a psychological services setting. Finally, clinicians were more likely to use self-report measures when the identified primary concern was a mood disorder or attention-deficit/hyperactivity disorder (ADHD). Based on these results, we provide suggestions and references to resources for clinicians seeking to improve the quality of their assessments via implementation of EBA. (PsycINFO Database Record (c) 2019 APA, all rights reserved).