As Mongolia’s economic development has fueled growing interest in music education, the demand for qualified music teachers in schools has steadily increased. This trend underscores the urgent need to strengthen the expertise of K-12 music teachers in Mongolia. In response, this study aims to examine the degree of their pedagogical expertise and challenges, with a view toward improving the overall quality of music education in the country.To guide the investigation, the study adopts the framework of Pedagogical Content Knowledge (PCK), introduced by Shulman (1986). PCK represents the integration of subject matter knowledge with pedagogical strategies, enabling teachers to communicate content effectively to learners. It has been widely applied in music education research (Kim, 2017; Manila, 2018; Milican, 2008, 2013). This study seeks to answer three research questions: 1) What is the level of PCK among Mongolian K-12 music teachers?, 2) Do levels of PCK differ according to teacher background(teaching school level, year of teaching career, and experience in music education)?, 3) What are the main challenges faced in teaching music?A mixed-methods design is employed to examine the PCK and challenges of Mongolian music teachers. Quantitatively, a questionnaire grounded in Shulman’s PCK framework and adapted from Mongolian music textbooks and Ministry of Education guidelines is being administered to K-12 music teachers. Data will be analyzed using SPSS: descriptive statistics will capture overall levels of PCK and teaching challenges, while t-tests will identify differences across teaching school level, year of teaching career, and experience in music education. Complementing this, qualitative follow-up interviews are being conducted to provide deeper insights into teachers’ expertise and challenges, expanding on the survey findings.Data collection, consisting of both surveys and interviews, is currently in progress and will continue throughout the semester, with results expected by its conclusion. At the conference, we will present the emerging findings on teachers’ PCK and the difficulties they encounter, highlighting their implications for teacher preparation and professional development. These insights are expected to inform strategies for strengthening the expertise of music teachers and, ultimately, advancing the quality of music education in Mongolia.