A total of 273 participants (186 with clinical dementia; 87 "normal" controls; mean age 72 years) in a prospective, longitudinal, dementia research study, underwent lumbar puncture (LP), where possible, on an annual basis. Reporting of symptoms after all LP's (n = 541) was 21.6%, the predominant complaints being mild localised back-pain (12.8%) and headache (10.7%). All symptoms were self-limiting. Analysis of headaches after all first LP's (n = 273) revealed an incidence of 14.2% with marked differences between subjects under 60 years of age (33%) and those over 60 years (10.1%), between subjects with "minimal" cerebral atrophy (19.5%) and those with "significant" atrophy (5.6%) and, to a lesser extent, between subjects with no or mild cognitive impairment (20.6%) and those with significant impairment (9.5%). Age under 60 years and lack of significant cerebral atrophy were shown to be independent predictors of headache. Acceptability of LP was high as demonstrated by agreement to a second procedure by 92.2% of eligible subjects. Our results show that LP can be successfully incorporated into research with the elderly.