OBJECTIVES: Few data exist on the impact of breast cancer (BC) on absenteeism and short-term disability (STD) to employers. This study was undertaken to estimate BC related indirect cost impacts within the US population. METHODS: This was a retrospective matched cohort study using a large health care claims database from a US national commercially-insured population (2003-2007). Women aged ≥18 were selected with ≥2 BC diagnoses on different dates within 90 days. The date of the first BC diagnosis was the index date for case cohort. The control cohort (without BC diagnosis) was selected with 1:1 matching to cases based on index date (same year and month), age (5 year range), region, employer, and health insurance type. Continuous enrollment for at least 6-months prior to and 12-months after the index date was required for both cohorts. Indirect cost was measured by days of absenteeism and STD, multiplied by age-matched average wage rates from Bureau of Labor Statistics. Two-part model was used to assess the 1-year post-index indirect cost difference between cases and controls with the adjustment of demographics, comorbid conditions, and pre-index total health care cost.   RESULTS: Based on the inclusion criteria, 856 and 2668 patients were selected for absenteeism and STD outcomes, respectively. Costs of absenteeism were $4972 and $2937, and costs of STD were $7199 and $653 for cases and controls, respectively, within the post-index year (both p<0.001). Two-part models predicted that the adjusted incremental costs for absenteeism and STD were $1911 and $6157 (p<0.001) per BC patient per year.   CONCLUSIONS: This study demonstrated that breast cancer is associated with approximately $8000 more in indirect cost per patient to the employer within the first year of diagnosis.