Background: The prevalence of developmental dysplasia of the hip (DDH) is unknown in China. We aimed to determine the prevalence of DDH in Chinese adults. Methods: In this study, we performed a cross?sectional survey of a nationally representative sample of Chinese adults. All participants underwent questionnaire investigation, physical examination, and X?ray examination. Factors associated with DDH were analyzed with logistic regression. Results: We invited 29,180 individuals aged 18 years and over to participate, randomly selected from 18 primary sampling units (street districts in urban areas and townships in rural areas). The survey and examination were completed in 25,767 people (10,296 men and 15,471 women). DDH was diagnosed in 391 people, yielding an overall DDH prevalence of 1.52%. Based on this information, we estimate the number of individuals with DDH in China to be approximately 16.05 million. DDH prevalence increased with age (odds ratio = 1.53 [1.03–2.27], P = 0.036), was significantly higher among women than men (2.07% vs. 0.75%, P < 0.001), and was higher among rural residents than urban residents (1.75% vs. 1.29%, P < 0.001). Economic development was independently associated with the presence of DDH. There was no evidence of an association between body mass index alone, education, or current smoking or drinking and risk of DDH (P > 0.05). Conclusions: DDH has become an important public health problem. Special attention should be paid to residents with DDH. Screening for DDH should be performed in China.