OBJECTIVE: Colorectal cancer (CRC) patients experience considerable psychological stress because of changes brought on by their illness. Religion may be a resource for such patients. We examined the prevalence of religious beliefs and practices in CRC patients and correlation with demographic, social, psychological, and physical health characteristics. METHODS: Seventy CRC patients (all Muslim) in Jeddah, Saudi Arabia, were surveyed using a 13-item Muslim religiosity scale. Standard measures were used to assess depressive symptoms, depressive disorder, and social support; demographic and social factors, psychiatric history, and disease factors were also measured. RESULTS: All 70 participants (100%) engaged in group worship and prayer (Fard) five times/day, and 75.7% never skipped or combined two or more obligatory prayers; 71.4% read or recited the Qur'an several times/week or daily; 80.0% gave money to the poor each year (Zakat); 71.4% fasted throughout the month of Ramadan (Sawm) and other times as well; 91.4% said they 'definitely' experienced the presence of Allah; and 74.3% said their entire approach to life was definitely based on their religious beliefs. Overall religiosity was inversely related to depressive symptoms (B = -0.58, SE = 0.30, p = 0.026) and suicidal ideation (B = -0.07, SE = 0.03, p = 0.025), after controlling for financial status and social factors. CONCLUSIONS: Religious involvement was widespread in this sample of CRC patients in Saudi Arabia and was related to fewer depressive symptoms and less suicidal ideation. No relationship was found with stage of disease or duration of treatment.