Background Job satisfaction in the nursing field directly impacts the quality of patient care. However, increased work demand puts nurses at a higher risk of job dissatisfaction, which can, in turn, affect their work performance. This study aimed to measure job satisfaction among nurses working in National Guard Primary Healthcare Centers (PHCs) and to determine the different sources of pressure at their workplace. Methods A cross-sectional quantitative study was conducted among nurses working in the National Guard PHCs in the Makkah region, Saudi Arabia, in 2022. A validated questionnaire from previous literature was used to evaluate nurses' job satisfaction. Results A total of 77 nurses completed the questionnaire, with an overall response rate of 89.5%. While 58% (n=45) of nurses were satisfied, 42% (n=32) were dissatisfied. Approximately half the participants were dissatisfied with the rate of payment (49%, n=38), working hours (47%, n=36), and future chances of promotion (44%, n=34). Moreover, 51% (n=39) of nurses attributed considerable pressure to staff shortage and 44% (n=34) to workload. Furthermore, lower mean satisfaction scores in nurses were significantly associated with their intention to leave their current center (p-value= 0.06). In addition, reduced satisfaction scores were frequently observed among females, singles, those who finished their first nurse training five to 10 years ago, those who had a previous experience outside the Ministry of National Guard Health Affairs (MNGHA), those who had only one to five service years, and the ones who belonged to centers that did not have clearly stated standards and policies for nursing practice. However, these associations were statistically not significant. Conclusion Results indicate that nurses' job satisfaction should be improved to decrease nurses' intention to leave their workplace and maintain their optimum performance in patient care. This can be achieved by addressing the sources of dissatisfaction and pressure at work.