Background and Rational: Improving quality of services is one of the main strategies of the Ministry of Health to strengthen health care services, aiming to provide better care. The Emergency Ward (ER) of Mahosot Hospital provides services to patients 24 hours a day. Since the work there is very busy, some complaints were arisen from the nurses regarding the workload, insufficient staffing levels, and staffs did not have time for families. In addition, three nurses asked to change their jobs and 6 ask to move to another ward. We, therefore, conducted this study to assess job satisfaction of the nurses and obstacles in regards to their work and management. Methodology: A descriptive cross-sectional study was conducted from 19-25 February 2018. Thirty-three nurses working in ER were interviewed using pre-designed and pre-tested questionnaire comprising 4 parts. Data analysis was done using SPSS. Result: The mean age of the respondents was 34.3 years, 85% were female and 73% were married. Nearly half of them did not have children. Thirty-nine percent of them have worked for 6-10 years with 73% having a nursing degree. The majority of them are satisfied with their current work (90.9 %) and 79% of them said that they had a great job with appreciation from their colleagues. More than half had the appropriate opportunity for short-course training and support from the head of department. Observing their practice, we found that they had clean nursing uniform (66.7%), showed appropriate behaviors (54.5%), friendly service (54.5%) and had good relationships with their colleagues (63.6%). Regarding the obstacles and solution, they reported that some problems need to be solved including those related to human resource (90.9%), relationships with other nurses (21.2%), head nurses (9%), doctors (27.16%), nature of workplace and environment (63%), facility and management (27%), equipment and medicine availability (72.7%), remuneration (51.5%) and others (30%). Conclusion The job satisfaction level of the nurses at ER of Mahosot Hospital is high but there remain some concerns related to work safety, working environment, equipment and salary. Therefore, it is vital that these problems should be solved urgently in order to strengthen quality of health care service.