More than 5% of the United States population has been diagnosed with nephrolithiasis and about one half of (first-time) stone formers will have a recurrence within 5 years. The prevalence of nephrolithiasis is concentrated among working age adults, yet little prior work has examined the economic burden of the disease on employers and their employees. We sought to estimate the direct and indirect costs of nephrolithiasis for working age adults (18-64) with employer-provided insurance.