Objective: This study was carried out to determine the knowledge levels of nurses working in Family Health Centers (FHCs) about childhood autism. Methods: This study is a descriptive and cross-sectional study. The sample of the study consisted of 361 nurses working in FHCs in the province with the highest child population rate in Turkey. Data were obtained using the personal information form and the Knowledge about Childhood Autism among Health Workers (KCAHW) questionnaire. Results: The findings show that the mean score for the KCAHW questionnaire was 10.95 ± 3.7. Gender, education level, previous employment in a mental health clinic, the presence of a person with autism in their environment or family, their previous participation in any autism-related education program, and knowledge of the autism screening and follow-up program conducted by the Ministry of Health significantly affected the scores that were obtained from the KCAHW questionnaire (p < 0.05). Conclusion: Educational practices that will increase the knowledge and awareness of nurses about autism can contribute to the diagnosis of children with autism at an earlier age.