Background: Frontotemporal dementia (FTD) causes progressive change in activities of daily living (ADLs) and little is known about their rate of decline. This study aimed to examine changes in ADLs, including subcomponents of initiation, planning or execution. Methods: A total of 72 ADL and general cognitive assessments were analysed. The patients were subdivided into behavioural variant FTD (bvFTD) pathological and phenocopy subgroups, semantic dementia (SemDem) and progressive non-fluent aphasia (PNFA). Results: Pathological bvFTD, SemDem and PNFA groups showed significant decline on ADLs after 12 months, while the phenocopy subgroup did not. In terms of subcomponents of ADLs, each variant showed different profiles of decline. The decline in ADL and cognitive scores were significantly correlated. Conclusions: FTD variants show differential annual rates of functional decline. The rate of decline should be taken into consideration when discussing prognosis.