Malignant diseases represent a significant public health problem since they are among the main causes of morbidity and mortality worldwide. The most difficult moment for a person is the diagnosis, that is the realization that person is suffering from a malignant disease. In this phase, the dominant emotions are anxiety, anger, fear, denial and despair. There are numerous risk factors for the development of malignant diseases and most of them can be influenced. They include cigarette smoking, alcohol consumption, inadequate nutrition, physical inactivity, chronic infections and genetic predisposition. Several procedures are used in the treatment of malignant diseases. If possible, surgery is performed first, which may be followed by chemotherapy or radiotherapy to prolong life. In comorbidity with malignant diseases, psychiatric disorders often occur and they greatly reduce the quality of life of the affected persons. Psychiatric disorders are thought to occur in 50% of patients diagnosed with a malignant disease. As the disease progresses, affected people almost always need the help of other people. According to the research, 93% of patients needed help from other people in one or more aspects; psychological or emotional support, provision of medical information, financial assistance, assistance with activities of daily living, spiritual and social needs. People are social beings, and it is known that social support has a positive impact on health as a whole. There are five basic types of social support; emotional support, support in the form of respect, instrumental support, informational support and support network. Malignant diseases are very exhausting both physically and mentally, both for the affected person and for their loved ones. It is important that family, friends and other close people realize the importance of providing support to the sick person. It can be a simple conversation, active listening or helping in the household. In addition to the sick person, it is very important to provide support to the family as well. The paper describes the most important features of malignant diseases, definitions and functions of the family. The types, importance and role of the nurse in providing support to sick people and families are further described, and a case report is attached at the end.