Background: With increasing budget cuts to education and social services, rigorous evaluation needs to document school nurses' impact on student health, academic outcomes, and district funding. Methods: Utilizing a quasi-experimental design, we evaluated outcomes in 4 schools with added full-time nurses and 5 matched schools with part-time nurses in the San Jose Unified School District. Student data and logistic regression models were used to examine predictors of illness-related absenteeism for 2006-2007 and 2008-2009. We calculated average daily attendance (ADA) funding and parent wages associated with an improvement in illness-related absenteeism. Utilizing parent surveys, we also estimated the cost of services for asthma-related visits to the emergency room (ER; N?=?2489). Results: Children with asthma were more likely to be absent due to illness; however, mean absenteeism due to illness decreased when full-time nurses were added to demonstration schools but increased in comparison schools during 2008-2009, resulting in a potential savings of $48,518.62 in ADA funding (N?=?6081). Parents in demonstration schools reported fewer ER visits, and the estimated savings in ER services and parent wages were significant. Conclusion: Full-time school nurses play an important role in improving asthma management among students in underserved schools, which can impact school absenteeism and attendance-related economic costs.