OBJECTIVES: to understand nurse participation in the process of early detection of warning signs of autism spectrum disorders (ASD) in childcare consultations. METHODS: qualitative, exploratory research, conducted through semi-structured interviews conducted between August and November 2022 with 27 nurses from family clinics in the city of Rio de Janeiro. The IRaMuTeQ® software was used for data treatment. Interpretations and theorizing were guided by Hildegard Peplau's Theory of Interpersonal Relations. RESULTS: lexical analysis pointed out thematic aspects related to the dynamics of development assessment, interpersonal relationship practices between nurses and family members as well as limits and interrelationships between healthcare professionals involved in early detection. FINAL CONSIDERATIONS: childcare consultations are characterized as a unique resource for the early detection of warning signs of ASD. Nurses need to be recognized as strategic agents in the face of this demand, especially in caring for socioeconomically vulnerable families.