Accrual to clinical trials continues to be a problem in many countries including Australia despite its fundamental importance to the progress of evidence-based medicine. This paper reviews the current literature addressing the obstacles to accrual excluding those related to protocol design. An electronic search of the literature identified publications in oncology specifically addressing the obstacles to participation in clinical trials. This search was supplemented by searches of key oncology journals. Obstacles fall into three main categories – clinician, patient and system; however, there are overlaps between categories. Clinician behaviour is the most important of these. Exclusion of patients for reasons other than defined eligibility criteria, concerns about increased time requirements, and suboptimal communication with patients all affect accrual. Risk management strategies for clinical trials need to be individualised to address the obstacles most likely to negatively impact on accrual. Communication between clinician and patient appears to be a greater issue than previously recognised. Time concerns need to be addressed as generational change affects the expectations of the medical workforce.