The global demographic shift towards an aging population raises concerns about the increasing prevalence of social isolation (SI) among older adults, a concern further highlighted by the recent COVID-19 pandemic. SI is associated with an increased risk of depression, anxiety, and cognitive impairment, exacerbating the global health issue of age-related cognitive decline. Research on the effects of SI in older animals is limited. However, in humans, the negative effects of SI become more pronounced with age, with a particularly strong effect on males. Our study examines the impact of SI on cognitive and motor function in aging male mice, providing insights that may be relevant to human outcomes. Male C57BL/6J/Ukj mice were isolated at 20 months of age for either 4 or 8 weeks. During the final 2 weeks of isolation, cognitive and motor function analyses were performed using the Barnes Maze and RotaRod tests, respectively. Post-isolation evaluations revealed no significant differences in motor function following SI, regardless of its duration. All cognitive parameters tested (learning, short and long term memory, cognitive flexibility) were impaired after 8 weeks of isolation, while 4 weeks of isolation showed no discernible effects when compared to group-housed controls. Our research indicates that extended periods of SI, especially in older individuals, can have adverse effects on cognitive function. This underscores the importance of comprehending the impact of social isolation stress on the elderly.