This study was prepared based on the findings of Seda Cansu Yeniğün's thesis study titled "The effect of sleep hygiene visual material use on sleep quality of patients before colorectal surgery" (Edirne: Trakya University; 2019).ABS TRACT Objective: Surgical intervention takes the first place in the treatment of colorectal cancer, and anxiety, fear and concern in the preoperative period may cause difficulty in meeting the sleep requirements of these patients. This study is to investigate the effect on patients, who will undergo colorectal surgery, of providing information on sleep quality through the use of sleep hygiene visual material. Material and Methods: This randomized controlled and quasi-experimental study was conducted on 62 patients with 31 patients in study group and 31 controls who were scheduled to undergo colorectal surgery in the general surgery department of a university hospital in Türkiye between January 25,2018 and June 28, 2018. Data were collected using patient identification form, Richards-Campbell Sleep Questionnaire, and sleep hygiene visual material. Patients in both groups who were hospitalized 2 days prior to surgery were visited by the researcher in their rooms and verbally informed about sleep hygiene. Sleep hygiene visual material was used for instructing the patients in the study group. Sleep quality was evaluated on the day before surgery and on the day of operation. Results: In this study, both groups were informed about sleep hygiene and this process was was significantly higher in improving the sleep quality of patients in both groups on the morning of the operation (p=0.000; p=0.000, respectively). The evaluation of the study group on the morning of the operation, found that the mean sleep quality total scale score of the study group was significantly higher when compared with that of the control group (p=0.043). Conclusion:In the study, it was found that using visual material of sleep hygiene in informing patients about sleep hygiene in the preoperative period contributed positively to improving sleep quality of the patients. We recommend the use of visual materials to help the patient remember information.