Campaigners spoke to more than 1,000 GPs across the country, and, The Yorkshire Post reports, found in Yorkshire alone, 41% did not think loneliness made a significant contribution to early death.
Earlier this week, a report also revealed that men who live on their own are more likely to die of skin cancer because they don't recognise or act on the symptoms.
But while campaigners say GPs are failing to make the connection between the more negative elements of a lonely lifestyle - poor diet, drinking and smoking - some GPs don't agree.
Dr Arun Ghosh, a private GP who practises in Liverpool, said family doctors were preparing themselves for big budget cuts and as a result, were focussing on more immediate medical issues, reported the MailOnline.
"I think it's distinctly unfair to blame doctors, for them to be responsible for social isolation of individuals. That has to be society as a whole there has to be intervention from the local council. I think it's distinctly unfair to blame doctors, for them to be responsible for social isolation of individuals. That has to be society as a whole."
Campaign to End Loneliness director Kate Jopling was quoted as saying: "As well as educating us about the dangers of an unhealthy lifestyle, doctors need to take an active role in addressing the root causes of poor health choices. When we are feeling lonely we are much less likely to look after ourselves.
"By helping people to maintain their social connections and relationships, or to make new ones, we can also help them to improve their health and ultimately reduce their chances of needing expensive medical care in later life."