Gilmerton Cove in Drum Street beat the city's castle, zoo and the National Museum of Scotland on a review website.
They reached number one on a list of Things To Do in Edinburgh. Tours of the network of tunnels and chambers opened 10 years ago.
Groups of just 12 visitors at a time are allowed in.
The origins of the hand carved tunnels, which are at least 300 years old, remain a mystery, with rumours of them being used as a drinking den for 18th Century gentry, a lair inhabited by Knights Templar or a refuge for Covenanters fleeing persecution.
Margaretanne Dugan, owner of Rosslyn Tours, which runs tours at Gilmerton Cove, said: "We only open if we have a booking but we're definitely seeing more and more interest, especially from overseas visitors.
"To be the top-rated attraction in Edinburgh is fantastic for such a wee place."
Gilmerton Cove consists of a 40ft corridor with rooms off either side, but Ms Dugan said there may be more tunnels yet to be uncovered.
She added: "All of the tunnels haven't even been explored as it is unsafe to do so."
Edinburgh City Council began to develop the site in 1998 after buying it for £1.
The attraction opened as a heritage centre after a £100,000 restoration project.
The 45-minute tour starts at a small mining cottage in Gilmerton, where visitors descend 16 steps to reach the chambers below.
The survey of attractions was run by the TripAdvisor review site.
Source: BBC News