Objective Recent research indicates considerable heterogeneity in the provision of memory assessment services (MAS). However, little is known on the extent of variation in the costs of the services MAS provide. We investigated the costs of supporting patients with suspected dementia, including assessment and support over the following 6 months. Methods Clinic costs were estimated on the basis of an organisational survey reporting staff roll, grade and activities. Costs of primary health and social care were estimated from questionnaire data reported by carers of patients at baseline, 3 and 6 months after referral. Results Mean monthly staff costs at MAS were £73 000. Imaging at assessment costs an additional £3500 per month. Monthly clinic cost per new patient assessed varied from £320 to £5400 across clinics. Additional primary health and social care costs of £130–220 a month between baseline and 6 months were reported by carers. Costs of pharmacological and non‐pharmacological treatments reported by carers were small. Informal care costs dwarfed health and social care costs when valued at a modest unit cost. The overall mean cost of supporting a patient for 6 months varied from £1600 to £2500 dependent on assumptions regarding the proportion of MAS intervention and review costs accrued at 6 months. Conclusions There is considerable variation in the intensity and associated costs of services provided by MAS. Further research should ascertain to what extent such variation is associated with differences in patient outcomes. Copyright © 2016 John Wiley & Sons, Ltd.