Rowan Rychel was a week away from turning two when her mother Francesca fainted suddenly and fell to the floor.
Mrs Rychel hit her head on a cabinet and twisted her leg in the incident at her home in Innerleithen in the Borders in September 2011.
Rowan, who was alone with her mother at the time, rang 999 and told the operator "mummy won't wake up".
Realising a child was making the call, police rushed to the scene, found the 28-year-old student nurse was unconscious and summoned an ambulance.
Rowan, now three, yesterday collected a meritorious award from Lothian and Borders Police.
Presenting the award at a ceremony in Edinburgh, a force spokeswoman said: "The officer involved was taken aback by Rowan's amazing actions and there's no knowing what might have happened had she not made that emergency call.
"Rowan's a credit to her family and we're pleased to honour her."
Explaining what she did that day, Rowan said simply: "Mummy bumped her head. I phoned a policeman."