Some evidence suggests that research and service clinics differ on treatment-relevant dimensions, but no study has examined whether research clinics (RCs) themselves differ. We compared 2 samples of children and adolescents (ages 7 to 17 years) with anxiety disorders treated in 2 different university-based child anxiety RCs, one in Philadelphia (n = 184) and one in Miami (n = 64), on child symptom and diagnostic measures, family characteristics (e.g., income), and level of maternal depression. The samples were not significantly different on any youth symptom and diagnostic measures except 1 (parent-reported diagnoses); further, the 2 samples were statistically equivalent on 3 of 6 youth symptom measures. Although the Miami sample had significantly more parent-reported diagnoses than the Philadelphia sample, the effect size was small (Cohen's d = 0.44). Statistically significant differences between the samples in ethnic background and family income were observed, though the former was not significant after controlling for population differences. Findings are discussed in terms of the implications of homogeneity of RCs for treatments tested there.