Background Since genetic factor is an important factor in the occurrence of cancer in colorectal cancer, risk awareness and knowledge level of first-degree relatives of patients with colorectal cancer is very important in cancer prevention. Aim This study was conducted to determine the knowledge level of first-degree relatives of colorectal cancer patients about colorectal cancer and their awareness of colorectal cancer risk factors. Method This is a descriptive study. 251 patients undergoing chemotherapy with a diagnosis of colorectal cancer in a university hospital constituted the sample of the study. The data were obtained by face-to-face interview method using the Information Form and the Questionnaire for the Evaluation of Knowledge and Awareness Levels of Colorectal Cancers. Results The mean score of the Questionnaire for the Evaluation of Knowledge and Awareness Levels of Colorectal Cancers was found to be 10.61 ± 5.65. This score indicated that individuals undergoing chemotherapy with a family history of colorectal cancer had a moderate level of knowledge and awareness about colorectal cancer. Two-thirds of the participants reported that they had knowledge that diabetes, obesity, lifestyle, smoking and alcohol use increased the risk of colorectal cancer. Conclusion The results revealed that It was observed that elderly, low educated, male and rural-dwelling participants needed more education on improving the level of knowledge and awareness about colorectal cancers. Implications for Practice: In order to prevent colorectal cancer and reduce the burden of disease, it is seen that first-degree patient relatives need to be more conscious and educated.