Loneliness should be treated as a "major public health issue", council leaders have said.
The Local Government Association (LGA) said that urgent action must be taken to address the issue.
The consequences of loneliness are "devastating and costly", the LGA said.
Charity Age UK said that the issue "blights the lives" of over a million older people.
"Loneliness is a significant and growing concern for many older people and is something that is now being identified as a major public health issue," said LGA spokeswoman for public health Izzi Seccombe.
"The impact of loneliness can be devastating and costly - with consequences comparable to smoking and obesity.
"This can be prevented with early intervention, which a number of councils are already successfully delivering in partnership with volunteer and community organisations."
Caroline Abrahams, Age UK's charity director, added: "Loneliness blights the lives of over a million older people, with many going for weeks without any meaningful human contact. It is a serious condition which can be enormously damaging, both mentally and physically."
The LGA plans to launch a new guide to help councils assist the elderly at its Annual Public Health Conference next week.