Kungsholmen police discovered the body of a man in an apartment after Sweden's Enforcement Agency asked for help in evicting him, the local.se reported Tuesday.
The man was paying his bills by direct debit but none of his friends, relatives or neighbors reported seeing him in the past 18 months.
Police traced unopened mail and food products inside the apartment to February of 2012.
"When someone has been lying there for so long it's impossible for police to determine the cause of death," said Viktor Adolphson of the Stockholm police.
In May, the body of a man in his fifties who had been dead for approximately two years was found in a south Stockholm flat.
"Society is getting harsher and harsher," Adolphson said. "Don't people notice that they've not seen the person next door?"