Background: Colorectal cancer (CRC) is the 3rd most common malignancy globally, and its disease burden is increasing rapidly in China. But CRC patients' knowledge and awareness of CRC have not yet been examined, which could facilitate the identification of targeted population from public for intervention. Methods: A nationwide multicenter cross-sectional survey was conducted in 19 tertiary hospitals (10 cancer hospitals and 9 general hospitals) from March 2020 to March 2021 in China. During study period, all Stage III and IV CRC patients were invited to complete a semi-structured survey that had been designed to collect information about their socio-demographic characteristics, and knowledge and awareness of CRC risk factors and screening. A multivariate logistic regression model was used to identify factors associated with their knowledge and awareness. Results: In total, 4,589 advanced CRC patients were enrolled in this study, of whom, 46.2% were from tertiary cancer hospitals, and 59.5% were male. Patients had a mean age of 60.1 +/- 11.6 years. Before diagnosis, 65.1% of the patients had no related knowledge of the CRC risk factors, and 84.9% were unaware of the CRC screening-related information. Only 30.4% of patients had actively sought to acquire CRC-related knowledge before diagnosis. The 3 most common knowledge sources were relatives or friends who had been diagnosed with CRC (13.2%), popular science television/broadcast shows (12.9%), and community publicity and education (9.6%). Generally, knowledge and awareness were positively associated with better education level [odds ratios (ORs) ranged from 1.49 to 2.54, P<0.001], annual household income ranged from 50,000 Chinese Yuan (CNY) to 100,000 CNY (OR =1.32, P<0.001), being manual laborer (OR =1.25, P<0.001) and being white-collar worker (OR =1.47, P<0.001). Conclusions: Advanced CRC patients' knowledge and awareness of CRC were severely limited before diagnosis. Thus, those who had limited knowledge and awareness should has a priority for intervention.