In this paper we review the published research that has investigated the psychological impact of arm morbidity associated with axillary dissection for early breast cancer. This critique is particularly timely given the drive towards minimally invasive techniques, such as sentinel node biopsy, which aim to reduce the incidence and severity of post-operative arm problems. Reported symptoms are multifactorial and include numbness, pain, swelling, weakness/stiffness, and restricted shoulder mobility of the affected arm. Conclusions from the few studies that have investigated the severity, incidence, duration and psychological impact of such disability are often limited by methodological problems. We identify these limitations and examine assessment tools used to determine the psychological impact of lymphoedema. The paper highlights the need for methodological rigor in study design, and the careful selection of appropriate, sensitive, reliable and clinically meaningful outcome measures to evaluate the impact of post-operative arm morbidity.