OBJECTIVES: Endometriosis is associated with significant direct and indirect cost burden. Little data exists on productivity losses due to endometriosis in the US METHODS: This analysis reports health productivity loss among endometriosis patients as captured by the Health-Related Productivity Questionnaire (HRPQ) made specific to endometriosis which was administered in an online comprehensive survey in 2012 to women aged 18-49 in the US. Analyses were limited to endometriosis patients who had not undergone hysterectomy and reported working one or more hours in the week prior to survey administration. ANOVA models were employed to assess the relationship between experiencing endometriosis-related pain symptoms and productivity losses.  RESULTS: Final sample included 810 women with endometriosis. Mean age was 35.2 years (SE=0.39); 18.1% were employed part-time, 73.8% were employed full-time, and 8.2% were self-employed. Patients were scheduled to work an average of 37.7 hours weekly. Endometriosis patients reported an average weekly loss of 6.34 work hours due to endometriosis (1.09 hours due to absenteeism and 5.26 hours due to presenteeism) which represented 16.9% of total weekly hours scheduled for work. Work hours lost due to absenteeism were higher among patients experiencing endometriosis-related pain symptoms compared to patients not experiencing them (pelvic pain/cramping during menstrual period: 1.2 vs. 0.8, p=0.32;  pelvic pain/cramping during non-menstrual period: 1.6 vs.0.7, p=0.06; pain during sex: 2.3 vs 0.5, p=0.003). For presenteeism, differences between women experiencing the symptom and those who were not were all significant:  (pelvic pain/cramping during menstrual period: 6.0 vs. 3.2, p=0.0004; pelvic pain/cramping during non-menstrual period: 6.6 vs.4.3, p=0.008; pain during sex: 7.2 vs 4.4, p=0.008). CONCLUSIONS: Endometriosis is significantly associated with productivity losses in the US which are primarily driven by presenteeism. Symptom improvement could reduce the significant patient and societal burden of endometriosis