Abstract Over the last 30 years many countries – including the UK – have seen a dramatic rise in the share of the working age population receiving sickness and disability benefits (hereafter disability benefits). This is despite health levels that are generally thought to be slowly improving. This paper describes the time path of UK disability benefit rolls and explores the existing UK literature together with literature from the USA in search of potential explanations for it. Since the early 1990s, despite a number of detailed descriptive studies, surprisingly little attention has been paid to quantifying the importance of the different factors believed to be driving the UK benefit roll growth. This is all the more surprising given the continued growth and the level of policy attention recently and currently devoted to disability benefits in the UK.