Fiumelatte is a river in northern Italy. It flows from a cavity in the Grigna into Lake Como, just south of Varenna, it has an approximate length of 250 m (820 ft). The name Fiumelatte, composed from fiume (Italian for "river") and latte ("milk"), is due to the milky white color of its water. One of the river's peculiarities is its annual intermittency: it usually dries in the middle of October to reappear in the second half of March; therefore it has been given the nickname Fiume delle due Madonne ("River of the two Madonnas"), alluding to the festivities of Annunciation (March 25) and Madonna del Rosario (October 7). This phenomenon could imply that the river is the vent of an unexplored underground cavity in the Grigna, which gets periodically filled.

The river is mentioned by the name Fiumelaccio in Leonardo da Vinci's Atlantic Codex:

It's the Fiumelaccio, which falls high from more than 100 ells from the vein where it is born, straight down on the lake, with inestimable uproar and noise.