Generalized anxiety disorder (GAD) is the most prevalent of the chronic anxiety disorders for older adults. Although a variety of self-report measures are beginning to be utilized to assess anxiety and related symptoms in older adults, there is a paucity of data regarding the convergence of self-report measures with clinician ratings of symptom severity. This situation is problematic in that interpretability of assessment data is limited, as is our broader understanding of the construct of GAD in an older adult population. To address these issues, we examined convergence across assessment modalities among 64 older adults who met diagnostic criteria for GAD. In addition to two Anxiety Disorders Interview Schedule for DSM-IV (ADIS-IV) interviews conducted by independent raters, participants completed four self-report measures (Penn State Worry Questionnaire [PSWQ], Worry Scale [WS], State-Trait Anxiety Inventory [STAI], Beck Depression Inventory [BDI]) as part of a more extensive pretreatment assessment battery. Results revealed significant correlations between clinician-rated GAD severity and the BDI, STAI, and PSWQ. Regression analyses indicated that the BDI (r2 = .15) and the PSWQ (r2 = .07) were particularly useful predictors of clinician-rated GAD severity. A comorbid mood disorder, however, was identified as an important mediator of these relations. Specifically, presence of coexistent depression accounted for 17% of the variance in clinician severity ratings (CSR; P < .01), with individuals diagnosed with a comorbid mood disorder receiving higher clinician severity ratings. The only self-report measure that accounted for additional significant variance was the PSWQ (7%). The study highlights the need to address coexistent psychological conditions when examining convergence between assessment modalities, and expands upon the relatively neglected area of anxiety assessment in older individuals. Specifically, the BDI and the PSWQ are identified as particularly useful screening instruments that may be helpful in conceptualizing GAD severity within an older adult population.