This study investigated the geometry knowledge of in-service primary school teachers through measuring both their content knowledge (CK) and pedagogical content knowledge (PCK) using a descriptive and qualitative approach. The participants of the study were 23 primary school teachers who work in public schools with teaching experience that ranges from six months to 30 years. The teachers voluntarily attended a teacher-training seminar conducted by the researchers and completed a test, which included open-ended questions. This particular study presented here is part of a larger design-based research project on a seminar that trains primary teachers to teach mathematics. The collected data were analysed through qualitative data analysis techniques with a holistic approach and discussion. The findings are presented according to the three geometric concepts that the study focused on: quadrilaterals, angle measurement and transformation geometry. On the whole, the study found that the CK of the primary school teachers was weak. We also found that the teachers' PCK was weaker than their CK due to the relationship between CK and PCK. Hence, primary school teachers should be offered additional teacher training sessions for the purpose of improving both CK and PCK, which will, in turn, enhance the learning opportunities of their students.