Introduction. Knowing that someone was entangled with cancer is a surprising experience for that person. Being aware of having cancer not only makes the person loose his hopes and ambitions, but also influences his body and mental. Meanwhile, religion can play the proper role of complementary treatment, increasing life expectancy in these patients.

Objective. The study was conducted with the aim of determining the relationship between praying and life expectancy in cancerous patients.

Method. This descriptive correlation study was performed on 96 malignant patients who were under chemotherapy in Golestan province in 1392. Paloma and Pendleton’s Measure of Prayer Type questionnaires and Schneider questionnaire of life expectancy were used to collect this information. Analyses were performed by using SPSS 21.0. Data were analyzed by using the linear regression and the analytical significance was set at p < 0.05.

Findings. The linear regression showed a significant relationship between life expectancy and praying (CI95:0.01-0.13), OR = 0.07, Beta = -0.24 P < 0.02) and in the light of previous experience it showed a significant relationship between praying and life expectancy.

Conclusion. According to the obtained result of this study, cancerous patients can overcome their illness through praying, and they can also triumph cancer through self-confidence and control it, by getting more knowledge of their disease and become more hopeful about their future.