Purpose - This paper seeks to investigate the reading behaviour of scientists from an intradisciplinary perspective. Design/methodology/approach - Different aspects of reading behaviour were studied including the amount of reading, the sources of reading, and the impact of factors such as age, academic status, academic activities and methods used for identifying articles on reading behaviour. The data were collected through a survey of 114 physicists and astronomers (faculty members and PhD students) at University College London. A total of 56 interviews were also conducted with PhD students and faculty members. Findings - The results revealed intradisciplinary differences within physics and astronomy in terms of reading behaviour. The study showed that recently published articles account for a large proportion of the readings. Age and academic status have an influence on the age of papers read. The amount of reading is influenced by the type of activities academics conduct, meaning those who spend more time teaching read fewer papers and those who spend more time doing research read more papers. Originality/value - The paper is the first to look at intradisciplinary differences within a single discipline and reveals the impact of some task-related and information-seeking factors on reading behaviour.