Objective: To evaluate the knowledge and behaviors of nurses on the oral health of pregnant women. Material and Methods: This was a qualitative study, whose data collection was performed with 12 nurses from Belém, Brazil, through questionnaire, with recorded interview applied by a single researcher, according to a semi-structured script composed of five guiding questions, and whose results were analyzed by Content Analysis. Results: Four thematic issues were originated: 1) "All have dental caries", referring to the nurse's perception on oral health related to the biological aspect; 2) "We refer", addresses the issue of nursing care and the nurse's responsibility for prenatal care; 3) "I do not know much", reveals the nurse's sometimes limited knowledge about oral health and discusses the breadth of dental care; and 4) "The demand is very large", brings up the view of nurses regarding the difficulties of accessing dental service in SUS. Conclusion: Nurses know prenatal protocols and refer patients to dental care, but their perception about dental care during pregnancy is not very comprehensive, which instigates the strengthening of interdisciplinary work.