OBJECTIVES: Compare annual indirect costs between privately insured employees with epilepsy and matched employee controls. METHODS: Employees with greater than or equal to 1 epilepsy diagnosis (ICD-9-CM: 345.x) in 2004, ages 18-64 years, were selected from a privately insured claims database containing disability data from 17 U.S. companies.  A random sample of age and gender matched employees without epilepsy was selected as a control group.  All were required to have continuous health coverage during 2004 (baseline) and 2005 (study period).  Chi-squared tests were used to compare baseline comorbidities and differences in indirect resource use (disability and medically-related absenteeism).  Wilcoxon rank-sum tests were used for univariate comparisons of mean disability and medically-related absenteeism days and associated annual indirect costs during the study period.  Two-part models were used to compare indirect costs adjusting for differences in demographic/clinical characteristics. RESULTS: Employees with epilepsy (n=1,866) averaged 48.4 years old (SD±10.4), and 55% were male.  Compared with controls, employees with epilepsy had significantly higher rates of mental disorders, substance abuse, other neurological disorders and physical disorders measured by the Charlson Comorbidity Index.  Employees with epilepsy were more likely to have a short- or long-term disability claim compared with controls (16.5% vs 5.6%, respectively; P<0.0001), resulting in higher mean number of annual disability days (38.6 vs 6.6, respectively, P<0.0001) and higher annual disability costs ($1836 vs $338, respectively; P<0.0001).  Medically-related absenteeism costs were also higher for employees with epilepsy compared with controls ($1356 vs $904, respectively; P<0.0001).  Average total indirect costs for employees with epilepsy were $3912 vs $1242 for controls (P<0.0001) and remained significantly higher after adjusting for patient characteristics ($2793  vs $1578, respectively; P<0.0001).CONCLUSIONS: Employees with epilepsy were three times more likely to have disability workloss, had six times the number of disability days, and three times higher indirect costs compared with matched employee controls.