Background: Nasopharyngeal Cancer (NPC) is diseases which ranked in the fourth position out of five majors of malignant tumor after cervical cancer, breast cancer, and skin cancer in Indonesia. The Public Health Center is a spearhead of health services in implementing various health programs that depended on some factors, one of them is the role of health workers. Goals: Exploring the description of health workers’ knowledge about nasopharyngeal cancer at the the public health center in Sleman Regency, Yogyakarta. Method: This research is including qualitative research by using phenomenology approach. The election of participants in this research used purposive technique sampling. The participants were including 7 health workers who consisted of 4 general practitioners and 3 nurses at the public health center in Sleman regency, Yogyakarta. Data collection is done by in-depth interview method using interview guides. Data analysis use the open code 4.02 application. Results: The findings of this research showed that the level of knowledge about nasopharyngeal cancer by nurses was in the level of knowing. Meanwhile, the general practitioners’ insight was in the level of knowing, understanding, applicating, synthesizing, and evaluating. Factors that affected the insight of the health workers about nasopharyngeal cancer consisted of the health workers experience, the health workers resource, and perception of general practitioners’ competency. Conclusion: health workers knowledge is very important in providing health services to the community. Therefore, health workers need to increase awareness to equip themselves and increase knowledge about the NPC.