ABSTRACT Objective: To evaluate the knowledge on developmental dysplasia of the hip (DDH) by professionals involved in its diagnosis. Methods: This is a cross-sectional study using questionnaires to assess the knowledge about DDH. Orthopedic surgeons and pediatricians, residents and medical students from a tertiary teaching hospital were included in the study. Results: We evaluated 142 medical students, eight orthopedic residents, ten pediatric residents, seven pediatricians, and nine orthopedic surgeons; 50% declared not having examined any DDH case in the last year and only three had diagnosed more than 10 cases during their career. Regarding self-assessed knowledge (0-10), the average score was 4.25 [n=186; SD=2.43]. Nineteen percent of the participants ignored semiological tests and 26.1% of pediatricians (specialists and residents), were unaware of how to perform them. The most acknowledged and neglected risk factor was pelvic presentation (68%) and CMT (9.3%), respectively. None of the participants were able to identify all the risk factors. The average number of risk factors identified was two (n=186; SD=1.58). Forty seven point three percent of the participants failed to recognize the time of birth as the ideal moment for diagnosis; 17% reported it was after the first month. Regarding neglected severe DDH, 45.3% failed to recognize its natural history. Conclusion: Knowledge on DDH among health professionals who are involved in screening is flawed. Level of Evidence IV, Developing a Decision Model.