Social isolation is a major and prevalent health problem among community-dwelling older adults, leading to numerous detrimental health conditions. With a high prevalence, and an increasing number of older persons, social isolation will impact the health, well-being, and quality of life of numerous older adults now and in the foreseeable future. For this review, a series of literature searches of the CINAHL, PsycINFO, and Medline databases were conducted, using the key words "social isolation," "social networks," "older adults," "elderly," "belonging," "perceived isolation," "social engagement," "social contacts," and "social integration," for the period of 1995-2010. The results show that there is an overabundance of evidence demonstrating numerous negative health outcomes and potential risk factors related to social isolation. However, there is scarce evidence that public health professionals are assessing social isolation in older persons, despite their unique access to very socially isolated, homebound older adults. Additionally, few viable interventions were found; therefore, it is advisable to focus on the prevention of social isolation in older adults. Public health professionals can take steps toward increasing the early assessment of social isolation and referring at-risk individuals to available community resources in order to prevent social isolation or further isolation, which would serve to reduce the numerous negative health outcomes associated with this condition.