The 50-year-old singer had been riding in The Hamptons, New York, when her mount was apparently startled by photographers.
Spokeswoman Liz Rosenberg told E! News: "The accident occurred when the horse Madonna was riding was startled by paparazzi who jumped out of the bushes to photograph the singer."
Rosenberg said that Madonna was treated for "minor injuries and bruises" at a Southampton hospital before being released.
Madonna vowed to ride again following an earlier fall in August 2005, in which she suffered a broken collarbone, three cracked ribs and a fractured hand.