Background: Social support, acknowledged as a protective factor against diseases, produces positive results in the prognosis of cancer patients. Objective: There is no relevant studies on perceived social support and factors related to Turkish cancer patients. Hence, the present study aimed to determine the demographic characteristics that affect the perceived social support in cancer patients undergoing chemotherapy in Turkey. Patients and Methods: This study was designed as a descriptive cross-sectional study. The sample included 423 adult cancer patients who admitted to the Outpatient Chemotherapy Unit of three hospitals in Turkey between March 2014 and August 2014. The data were collected through Demographic Characteristics Form and Cancer-Specific Social Support Scale (CPSSS). Results: Patients were between 19 and 85 years of age with a mean 51.75 years. Almost half of them (40.7%) were primary school graduates, 53.2% were female, 84.6% were married and 85.8% had children. It was found that the patients generally received a high score (127.86 17.44) from the CPSSS scale. The highest scores were obtained on the Confidence Support sub dimension. It was revealed that women and married patients needed more confidence support and general social support (P < 0.05). Social support perceived by primary school graduates was statistically significant to a great extent (P < 0.05). In spite of the difference between the patients with metastasis and their perceived social support grade averages (P 0.05), it was seen that patients with multiple children utilized more confidence support and general social support in social support reception (P < 0.05). Conclusion: The study showed that study participants received a high amount of social support. Age, gender, marital status, number of children, and educational status were determined to affect perceived social support. It is recommended to support the patients who do not receive sufficient social.