The aging process is associated with social changes, among all the modifications that it entails. Relationship networks are transformed and/or impoverished, they may decrease. A decrease in social activity is possible and all these accumulated changes contribute, or can contribute, to increase the vulnerability of the elderly to experience loneliness. Loneliness is a concept that has been studied by several areas of knowledge, however it remains difficult to define. Objective: describe the dimensions and indicators of the concept of loneliness perceived by elderly who use social and health institutions. Methodology: Systematic Literature Review, through research at EBSCO, selecting the CINAHL and MED-LINE databases. Results: After analyzing the chosen studies, 5 dimensions of the concept of loneliness were identified. Indicators were also identified by the use of expressions/reports by the elderly in the analyzed studies. Conclusion: The "Absence of significant relationships", "the lack of distraction" and "social isolation" are referred in the majority of the 9 articles analyzed. We can affirm that the relational and social isolation dimensions are valued, compared to the other dimensions identified. Health professionals must know the concept of loneliness perceived by the elderly to intervene. Moving to nursing homes can bring security and social support, but when it fails it can aggravate some of the indicators of loneliness of various dimensions. All participants in the studies analyzed were able to collaborate in the investigations, the non-verbal component was not explored, revealing a limitation in this review.