OBJECTIVE: To investigate the effects of physical exercise during work hours (PE) and reduced work hours (RWH) on direct and indirect costs associated with sickness absence (SA). METHODS: Sickness absence and related costs at six workplaces, matched and randomized to three conditions (PE, RWH, and referents), were retrieved from company records and/or estimated using salary conversion methods or value-added equations on the basis of interview data. RESULTS: Although SA days decreased in all conditions (PE, 11.4%; RWH, 4.9%; referents, 15.9%), costs were reduced in the PE (22.2%) and RWH (4.9%) conditions but not among referents (10.2% increase). CONCLUSIONS: Worksite health interventions may generate savings in SA costs. Costs may not be linear to changes in SA days. Combing the friction method with indirect cost estimates on the basis of value-added productivity may help illuminate both direct and indirect SA costs. CopyrightÂ