Aim: To describe the lived experiences of Registered Nurses at the Sangre Grande hospital, Trinidad and Tobago, who have only basic Nursing training but are required to clinically manage oncology patients with Brain Tumours. Background: Seventy-five (75%) of admissions to the Sangre Grande Hospital, on a daily basis, are Oncology long stay patients, who are admitted onto the medical ward. Lack of training in this specific area of expertise created feelings of inadequacy and work dissatisfaction among those Nurses. Method: Qualitative phenomenological design was employed to garner information from six (6) Registered Nurses from the Sangre Grande hospital, who have the basic Nursing Training and are directly responsible for the clinical management of patients with Brain Tumours were interviewed. The interviews were coded and analysed using Teschs’ method of open coding. Results: The RNs responses were grouped into five (5) major themes: The need for Oncology training for RNs; the need for Oncology facilities and support for RNs, patients, and relatives; the Physical impact/toll on RNs; the Psychological impact/toll on RNs; and RNs’ challenges interacting with patients. Conclusion: The results mainly revealed that it was psychologically and physically demanding and frustrating for RNs to function in this specific areas of expertise with only basic Nursing training. These results were congruent with the results received in similar studies by Poggenpoel, Myburgh, and Morare (2011) in Johannesburg, South Africa, and Johansson and Lindhal (2012) in Sweden.