Medication errors have significant health and economic consequences. Monitoring medication errors by implementing monitoring systems proved in the USA and European countries since 1990s to be an effective method for error detection, leading to improved safety at all levels of health care. Currently, China does not have a universal medication error monitoring system. To evaluate the effectiveness of the Medication Error Monitoring System for the reduction of medication errors in Xiamen Maternity and Child Care Hospital. Between January-June 2014, the Medication Error Monitoring System developed by Xiamen Maternity and Child Care Hospital was employed to monitor medication errors through error reporting by physicians and pharmacists. The errors collected by this system were then thoroughly assessed and addressed by specific improvements including more frequent training, introducing computerised prescribing systems and a bar-coding medicine dispensing system. Data collected from January-June 2015, was then compared with the data collected in 2014 to determine whether medication errors had been reduced. Between 2014 and 2015, the total medication errors in prescribing and dispensing were reduced by approximately 27%. Compared with 2014, there was a marked reduction in the number of errors due to misdiagnoses and inappropriate usage/dosage in 2015, while the number of data entry errors increased and became the most common cause of medication error. The success rate of pharmacy interventions increased from 95.25% to 96.88%, albeit modest. However, across all medication errors in the stage of prescribing and dispensing, non-human-related errors significantly decreased from 44.25% in 2014 to 37.94% in 2015 with apvalue of 0.021. The Medication Error Monitoring System is effective at monitoring medication error data, leading to a reduction in reported medication errors. Better training for hospital staff including doctors and pharmacists will be critical to reduce human-related medication errors in the hospital.