Objective: Cognitive impairment is a hallmark of mild cognitive impairment (MCI) and Alzheimer’s disease dementia (AD). Although the cognitive profile of these patients and its association with activities of daily living (ADLs) is well documented, few studies have assessed deficits in fine motor dexterity and their association with ADL performance. The objective of this research paper is to evaluate fine motor dexterity performance among MCI and AD patients and to investigate its association with different aspects of ADLs. Methods: We assessed normal aging controls, patients with multiple- and single-domain amnestic MCI (aMCI), and patients with mild AD. Fine motor dexterity was measured with the Nine-Hole Peg Test and cognitive functioning by the Mattis Dementia Rating Scale. We analyzed the data using general linear models. Results: Patients with AD or multiple-domain aMCI had slower motor responses when compared to controls. AD patients were slower than those with single-domain aMCI. We found associations between cognition and instrumental ADLs, and between fine motor dexterity and self-care ADLs. Conclusion: We observed progressive slowing of fine motor dexterity along the normal aging-MCI-AD spectrum, which was associated with autonomy in self-care ADLs.