The present study explores the relations between work hours and the difficulty in leaving work on time to both work-to-family conflict (WFC) and burnout among female workers in Taiwan. A cross-sectional research design and questionnaire were employed to obtain the research data. In total, 738 full-time female workers took part in the study. The results of regression analyses showed that when age, marital status, economic status, occupation, parental status, and housework responsibilities were controlled, more work hours were positively associated with WFC and burnout. When the difficulty in leaving work on time was also considered in the analysis, long working hours were still significantly associated with burnout; however, the significant relation with WFC disappeared. It is surmised that if female employees work overtime voluntarily, the perception of WFC diminishes; nevertheless, the adverse effect of long working hours on health remains unabated. This study concludes that female employees who work overtime on a voluntary basis are at risk of health problems, which should be a focus of concern.