Postpartum hemorrhage (PPH) is a leading cause of maternal mortality in Nigeria and in most low- and middle-income countries. The World Health Organization (WHO) strongly recommends oxytocin as effective, affordable, and the safest drug of first choice in the prevention and treatment of PPH in the third stage of labor. However, there are concerns about its quality. Very high prevalence of poor-quality oxytocin, especially in Africa and Asia, has been reported in literature. Excessive and inappropriate use of oxytocin is also common in low-resource settings.To assess clinical experiences with quality of oxytocin used by healthcare providers in Lagos State, Nigeria.This was a descriptive cross-sectional study conducted in 2017, with 705 respondents (doctors and nurses) who use oxytocin for obstetrics and gynecological services recruited from 195 health facilities (public and registered private) across Lagos State. Data collection was quantitative, using a pretested self-administered questionnaire. Data analysis was performed with IBM SPSS version 21. Statistical significance was set at 5 percent (p<0.05). Ethical approval was obtained from Lagos University Teaching Hospital Health Research Ethics Committee.Only 52 percent of the respondents knew oxytocin should be stored at 2°C to 8°C. About 80 percent of respondents used oxytocin for augmentation of labor, 68 percent for induction of labor, 51 percent for stimulation of labor, and 78 percent for management of PPH. Forty-one percent used 20IU and as much as 10% used 30IU to 60IU for management of PPH. About 13 percent of respondents reported believing they had used an ineffective brand of oxytocin in their practice. Just over a third (36%) had an available means of documenting or reporting perceived ineffectiveness of drugs in their facility; of these, only about 12 percent had pharmacovigilance forms in their facilities to report the ineffectiveness.The inappropriate and inconsistent use of oxytocin, especially overdosing, likely led to the high perception of medicine effectiveness among respondents. This is coupled with lack of suspicion of medicine ineffectiveness by clinicians as a possible root cause of poor treatment response or disease progression. Poor knowledge of oxytocin storage and consequent poor storage practices could have contributed to the ineffectiveness reported by some respondents. It is necessary to establish a unified protocol for oxytocin use that is strictly complied with. Continuous training of healthcare providers in medicine safety monitoring is advocated.