The National Cataract Surgery Survey is a prospective cross-sectional survey of surgery for age-related cataract within the National Health Service. It is the first national study of cataract surgery in the United Kingdom providing clinical data. This is the first in a series of papers and describes a profile of the characteristics of patients admitted for cataract surgery that includes: demography, referral sources, presence of co-existing ocular pathology, level of visual impairment on admission and waiting time for surgery. A profile of the process of the surgical procedure for 1990 is also described: number of operations performed, type of admission, type of anaesthetic, cataract extraction and intraocular lens and the grade of surgeon performing the procedure.