The goals of this study are to (a) inform clinicians embarking on evidence-based screening initiatives about what to expect when using quality tools, including provision of information on identification rates by age, patient mix, and well-visit uptake, and (b) describe the various implementation methods used by other clinics. Participants were professionals in 79 clinics across 20 U.S. states and elsewhere in North America, collectively serving 20,941 families via a Web-based screening ervice, PEDS Online®, which offers developmental-behavioral/mental health and autism screens with automated scoring, report writing, and a mineable database. Problematic screening results were found in more than 1 out of 5 children, and rates of screening test failures increased with children’s ages. Children screened outside the well-child visit schedule were more likely to have screening test failures. Personnel at 22 of the 79 clinics were either interviewed or observed in person to identify implementation strategies. Clinics, even those serving families with limited education or lack of facility with English, found a variety of ways to make use of online screening services.