Older adults with subjective cognitive decline (SCD) are at high risk of developing dementia and frequently experience subclinical symptoms (e.g., anxiety, depression) which are themselves associated with dementia and cognitive decline risk. To date, the lack of effective disease-modifying treatments, along with the reliable identification of modifiable lifestyle risk factors (e.g., cognitive activity, dietary habits, physical exercise), have led to growing interest to invest in non-pharmacological interventions that may reduce the prevalence and incidence of dementia and cognitive decline in older adults. In this framework, the aim of this project is to evaluate the efficacy of an Immersive Virtual Reality (IVR) and telemedicine-based multi-component intervention, combining cognitive training and a health and lifestyle education program, for preventing cognitive decline and dementia in at-risk individuals (i.e., SCD). For this purpose, a randomized, double-blinded controlled trial (RCT) will be conducted on seventy-five eligible individuals with SCD, who will be randomly assigned to one of three conditions: (a) multi-component intervention (MC-I), including SCD-tailored cognitive IVR training plus a health and lifestyle education program, (b) cognitive-only intervention (CO-I), including the SCD-tailored cognitive IVR training plus an active control for the education program, and (c) active control intervention (AC-I) for both cognitive training and education program. Intervention will be provided in 20 at-home sessions (4 sessions/week, each lasting about 30 minutes) over a period of 5 weeks. Outcome measures include clinical, neuropsychological, behavioural and neuroimaging data that will be collected before and immediately after intervention in order to detect potentially intervention-induced changes in objective cognitive functioning (primary outcome), subjective cognitive functioning, mood, quality of life and brain connectivity (secondary outcome). Users' compliance with IVR and telemedicine approach will be also evaluated, as well as individuals' factors affecting training efficacy.