Background: Depression is prevalent among children and adolescents and often goes untreated with adverse effects on academic success and healthy development. Depression screening can facilitate early identification and timely referral to prevention and treatment programs. Conducting school-based emotional health screening, however, raises the controversial issue of how to obtain informed parental permission. Methods: During implementation of a depression screening program in an urban school district in the Pacific Northwest, the district's parental permission protocol changed from passive (information provided to parents via a school mailer with parents having the option to actively decline their child's participation) to active (information provided to parents via a school mailer requiring the written permission of the parents for their child's participation). This change provided an opportunity to examine differences in participation under these 2 conditions. Results: A total of 1533 students were enrolled in this program across both years. Compared to conditions of passive permission, participation was dramatically reduced when children were required to have written parental permission, dropping from 85% to 66% of eligible children. Furthermore, under conditions of active parental permission, participation decreased differentially among student subgroups with increased risk for depression. Conclusions: Successful implementation of school-based emotional health screening programs requires careful consideration of how to inform and obtain permission from parents. (Contains 2 tables and 1 figure.)