The men were working nearby when a blaze broke out at a first-floor flat in Toryglen in Glasgow's South Side.
They rushed to the scene with a ladder after spotting a mother at the window.
She was able to lower her seven-month-old baby and four-year-old child to one of the workmen from the flat in Corlaich Drive.
Their ladder was agonisingly short, but she managed to lower the children within grasp of the rescuers.
The woman remained trapped in the blazing flat until firefighters arrived minutes later.
Crews carried a nine metre ladder through the close to the rear of the property, where they helped her climb to safety.
Both children and their mother were checked by ambulance staff but did not require hospital treatment.
The fire caused major damage to the flat and smoke damage to surrounding properties.
Strathclyde Fire and Rescue praised the workmen. Group Commander Roddie Keith said yesterday: "The workmen who helped the children did an excellent job and should be commended."