In the UK, researchers' access to study populations and control over selection of participants is becoming increasingly constrained by data protection and research governance legislation. Intervening stages placed between researchers and the population they wish to study can have serious effects on recruitment and ultimately on the validity of studies. In this paper we describe our experiences of gaining access to patients for a study of palliative care in primary care. Despite considerable time and resources dedicated to recruitment, a smaller than anticipated study sample was achieved. We found that gatekeeping by ethics committees and practitioner control over sample selection were significant hurdles in accessing patients for the study. Gatekeeping responsibilities represent considerable challenges for researchers seeking to obtain a representative study sample, not just in palliative care, but for research in general in health care.