With more rapid advances in potential treatments for brain tumours, the number of clinical trials for brain tumour patients is rising. In the context of the challenges of recruitment and enrollment of patients with brain tumors, the dichotomy between the paucity of subjects and abundance of clinical trials creates a unique ethical dilemma, whereby a single patient may be eligible for several studies. Here, we identify and present three approaches for recruiting and enrolling patients who may be eligible for several trials. The ethical implications of the full disclosure, paternalistic, and random approaches are discussed. The full disclosure approach presents information to patients regarding all ongoing concurrent trials, allowing them to make an informed decision, while the paternalistic approach allows the healthcare providers to select the trial for which they believe the patient is most suitable. These introduce the biases into circumstances where equipoise is necessary and risk selection bias in study design. The random approach randomly allocates patients to each trial, which may erode patient autonomy and decrease trial enrollment. Brain tumor patients comprise a vulnerable population and it remains incumbent on healthcare providers to maintain the highest ethical standards when approaching them for clinical research. Changes in clinical trial design are required to mitigate the conflicts created by competition for patients.