BACKGROUND: Productivity loss is an overlooked aspect of the burden of chronic health conditions. While modern guidelines emphasize achieving clinical control in asthma management, few studies have reported on the relationship between asthma control and productivity loss. We calculated the productivity loss that can be avoided by achieving and maintaining clinical control in employed adults with asthma. METHODS: We prospectively recruited a population-based random sample of adults with asthma in British Columbia, Canada. We measured productivity loss due to absenteeism and presenteeism using validated instruments, and ascertained asthma control according to the GINA (Global Initiative for Asthma) classification. We estimated the average gain in productivity for each individual if the individual’s asthma was controlled in the past week, by fitting two-part regression models associating asthma control and productivity loss, controlling for potential confounding variables. RESULTS: The final sample included 300 employed adults (mean age, 47.9 years [SD 12.0]; 67.3% women). Of these, 49 (16.3%) reported absenteeism, and 137 (45.7%) reported presenteeism. Productivity loss due to presenteeism, but not absenteeism, was associated with asthma control. A person with uncontrolled asthma would avoid $184.80 (Canadian dollars [CAD]) in productivity loss by achieving clinical control during a week, CAD$167.50 (90.6%) of which would be due to presenteeism. The corresponding value was CAD$34.20 for partially controlled asthma and was not statistically significant. CONCLUSIONS: Our results indicate that substantial gain in productivity can be obtained by achieving asthma control. Presenteeism is more responsive than absenteeism to asthma control, and, thus, is a more important source of preventable burden.