Objective: The aim of this study was to evaluate whether or not there were changes in the behaviors of relatives of cancer patients such as learning the warning signs of cancer, engaging in cancer prevention strategies, and participating in screenings after education sessions in the clinic. Methods: This one-group pretest-posttest study was conducted with 238 relatives in a medical oncology clinic in Antalya, Turkey. Individual education sessions were conducted as an intervention, banners were hung about cancer, and general health information on checkups in the form of leaflets were distributed to each relative regarding cancer screenings. Reminder messages were sent to individuals to participate in screenings one and two months after the first interview. The posttest data were collected by phone in the third month. Four questionnaires were prepared based on the literature and national cancer screening standards. The face validity of the tools was evaluated by three experts and 15 relatives who not included as participants. Results: The rate of having a mammography increased from 19.8% to 33.9%, rates of having the fecal occult blood test increased from 16.9% to 23.8%, and rates of having the HPV test increased from 43.5% to 49.6%. The rate of having blood pressure checks within the last 12 months increased from 75.8% to 83.1%, rates of blood cholesterol measurement increased from 68.5% to 79%, and rates of blood glucose measurement increased from 70.2% to 79%. Conclusion: Education provided to the relatives increased participation in screenings.