Cancer is a process which leads the patients and the caregivers think about death at every stage of diagnosis and treatment besides being a severe, chronic disease. Surgical procedures and radio-chemotherapy are the main causes of worries not only for the patients but also for the caregivers. The aim of this study is to investigate the prevalence of depression and anxiety developing before and during chemotherapy among cancer patients and their primary caregivers and to determine related factors. A total of 287 oncology patients who were receiving chemotherapy at Medical Oncology Department of Celal Bayar University Medical School between June 2011 and January 2013 and their primary caregivers were included in the study. Four interviews were done, one at the time of admission to Medical Oncology De-partment and at every 3 months, and patients were applied SF36 Quality of Life Scale, caregivers were applied Beck Depression Scale and Beck Anxiety Scale. 45,6% of the patients and 44,9% of the caregivers were between ages 41-60 years. Of the oncology patients, 41,5% were female and 55,7% were male. Anxiety was detected in one-third of the caregivers beginning from the 2th control, depression was detected in 12,2% at the time of first admission and 34,4% and 39,3%, respectively on the first and forth controls. Prevalence of depression was found 67 fold greater and prevalence of anxiety was 19 fold greater among the caregivers of the patients who had a progressive disease. Female gender and low education status were found as the anxiety and depression-related risk factors for the caregivers at the time of first admission and on controls. Female gender, low education status, presence of a progressive disease lead to an increased prevalence of anxiety and depression for the caregivers. Impaired physical functioning was detected to be significantly associated with anxiety; impaired social functioning was detected to be significantly associated with depression in the caregivers. Assessment of the caregivers together with the patients at the time of admission and during follow up may decrease prevalence of depression and anxiety.