Background: Non-adherence occurs in various groups of patients, including those with chronic diseases. One strategy to increase adherence among oncological patients is to individualise treatment and expand pharmaceutical care. Pharmaceutical labels that remind patients how they should take their medications are of great importance in this respect. Objective: The main objective of this study was to evaluate medication adherence in oncological patients, and to gather their opinions on the individual medication labelling system as an element of effective treatment. Methods: The study was conducted in 2021 among 82 patients of the oncological department of the Centre of Oncology in Radom. The research tool was a questionnaire consisting of personal data and two parts relating to the patient’s disease and the medication labelling system. Results: Nearly half of the respondents reported that they forget to take medications and how they should take them. These problems increased with the age of the patient and the number of administered medications. Of the respondents, 89% stated that the labels with dosing information are helpful. Over 67% agreed that these labels should be affixed to all medications. Nearly 90% of the respondents believed the labels should be available in all pharmacies. Conclusions: Non-adherence is a common phenomenon among oncological patients. Pharmacists providing a labelling service for medicinal products can play a significant role in reducing this phenomenon.