Evidence-based practice (EBP) has been a priority in health care in recent decades. However, few studies have investigated EBP in primary care. The aim of this study was to explore the knowledge that nurses with a bachelor's degree use in their clinical practice of primary care. Focus group interviews were used. The sample consisted of 20 nurses in primary care practice. The data were analysed with systematic text condensation. Our findings show that most nurses use their own knowledge, their colleagues' knowledge, knowledge acquired during nursing education, nursing literature, and guidance from expert personnel, but seldom use research. We recommend improving and developing the clinical practice of primary care. Referring to and analysing specialist and scientific data about specific topics may lead nurses to critically evaluate their clinical practice, and may enhance their theoretical and scientific knowledge related to clinical practice.