Background. Asthma is the most common chronic childhood illness and the leading cause of missed school days. School is a potential location for establishing an asthma education program for children and their parents/caregivers designed to improve disease management. Objective. To determine whether a comprehensive, school-based asthma management program, in addition to a conventional disease management program, can reduce measures of asthma control, student absenteeism, and caregiver lost workdays. Methods. School nurses recruited parents/caregivers of students with asthma from three urban elementary and middle schools. Children were identified as having asthma by a previous diagnosis from their personal physician. Parents were invited to attend educational sessions about the program. Students received peak flow meters and training in their use and had access to an interactive asthma diary to record symptoms, peak flow, and medicine usage. They received monthly asthma education at school and had access to an online asthma education program and additional handouts. Parents received several educational calls regarding asthma and had a 24-hour, 7-days-a-week emergency number to call if problems arose. Results. At 6 months, missed school days and unscheduled doctor visits were reduced by two thirds (n = 41; p < 0.01 for each). Caregivers' perception of children's activity level increased by 11% (n = 26; p = 0.037). Daytime and nighttime frequency of symptoms dropped by 62% and 34%, respectively (n = 32; p < 0.007 and p < 0.03 for each). These trends continued at 12 months, although only reduction in frequency of symptoms attained statistical significance. Conclusions. A comprehensive, school-based asthma management program can successfully improve asthma control and reduce absenteeism in elementary and middle school students and caregiver lost workdays.