Background: Organic solvents have been suggested to increase the risk of breast cancer although the epidemiologic evidence is limited. This study explored the association between organic solvents and breast cancer. Methods: This nested population-based case-control study comprised 845 women with primary breast cancer initially identified in the Danish Cancer Registry between 2000 and 2003, and 1500 controls matched on year of birth who were randomly selected from the Danish Civil Registration System. Information on occupational exposure to organic solvents, and specifically ethanol, as well as risk factors for breast cancer was collected through structured interviews. Results: For organic solvents, an increased risk was indicated for ever-exposure (odds ratio = 3.20, 95% confidence interval: 2.27–4.52), however, no noteworthy risk patterns were detected when exploring duration of exposure and cumulative exposure. Ever-exposure to organic solvents was associated with an increased risk of estrogen receptor negative and positive tumors as well as pre- and postmenopausal breast cancer. No associations were detected between occupational exposure to ethanol and breast cancer. Conclusions: This study indicates a positive association between organic solvents and breast cancer.