Objective: Nursing students who take care of the patient in clinical area practices as a part of their internships in primary health care and clinical areas, should be aware of the warning signs of cancer so that they may inform the community about them. Methods: This study was conducted to determine the awareness of nursing students about the warning signs of cancer. The research was planned as a descriptive and cross-sectional study. The research was completed with 460 nursing students between February 2019 and May 2019. Results: The average age of the students participating in the study was 20.05 +/- 2.04 years. Female nursing students were more familiar with the warning signs of cancer, than male nursing students. Second, third- and fourth-grade nursing students knew the warning sign of better than the first graders. More nursing students who had taken the internal diseases nursing course knew the warning sign of better compared to the students who did not take the course. Nursing students with a family member with a history of cancer knew the warning better than those who did not have a family history of cancer. Thickening or lump in the breast or elsewhere" was the most known warning sign of cancer (92.6%), whereas the least known sign was "indigestion or difficulty in swallowing" (47.0%). Conclusions: Female nursing students those who had taken the internal diseases nursing course and those who had a family member with a history of cancer were more aware of the warning signs of cancer.