It is well-known that chemotherapy brings about various adverse physical effects such as fatigue, nausea, or vomiting, and that it lowers mental well-being. It is less known that it desynchronizes patients with social environment. This study explores the temporal aspects and challenges of chemotherapy. Three groups equal in size and distinguished according to weekly, biweekly, and triweekly treatment schemes, each independently representative in terms of sex and age of the cancer population (total N = 440) were compared. The study found that chemotherapy sessions, regardless of their frequency, patients’ age, and the overall length of treatment, have a very large effect on changing the felt pace of time from flying to dragging (Cohen’s d = 1.6655). Most patients pay more attention to the passing of time than before treatment (59.3%), which has to do with the disease (77.4%). They also experience the loss of control over time, which they subsequently attempt to regain. The patients’ actual activities before and after chemotherapy, however, are mostly the same. All these aspects create a unique 'chemo-rhythm', in which the significance of the type of cancer and demographic variables is negligible, and the mere rhythmic nature of treatment plays a central role. In conclusion, patients find the ‘chemo-rhythm’ stressful, unpleasant and difficult to control. It is vital to prepare them for it and help to reduce its adverse effects.