Background: Massachusetts (MA) mandated body mass index (BMI) screening in schools in 2010. However, little is known about pediatricians' views on school-based screening or how the pediatricians' perspectives might affect the school-based screening process. We assessed MA pediatricians' knowledge, attitudes, beliefs, and practices concerning BMI screening. Methods: An anonymous Web-based survey was completed by 286 members of the MA Chapter of the American Academy of Pediatrics who provided primary care (40% response rate). Results: Support for school-based BMI screening was mixed. While 16.1% strongly supported it, 12.2% strongly opposed it. About one fifth (20.2%) believed school-based screening would improve communication between schools and pediatricians; 23.0% believed school-based screening would help with patient care. More (32.2%) believed screening in schools would facilitate communication with families. In contrast, pediatricians embraced BMI screening in practice: 91.6% calculated and 85.7% plotted BMI at every well child visit. Pediatricians in urban practices, particularly inner city, had more positive attitudes toward BMI screening in schools, even when adjusting for respondent demographics, practice setting, and proportion of patients in the practice who were overweight/obese (p less than 0.001). Conclusion: These data suggest MA pediatricians use BMI screening and support its clinical utility. However, support for school-based BMI screening was mixed. Urban-based pediatricians in this sample held more positive beliefs about screening in schools. Although active collaboration between schools and pediatricians would likely help to ensure that the screenings have a positive impact on child health regardless of location, it may be easier for urban-based schools and pediatricians to be successful in developing partnerships. (Contains 5 tables.)