Tanaro (French: [ta.na.ʁo]) was a short-lived department of the French First Republic and of the First French Empire in present-day Italy.

It was named after the river Tanaro.

It was formed in 1801, when the Subalpine Republic (formerly the mainland portion of the Kingdom of Sardinia) was intended to be annexed to France.

The department was disbanded in 1805, when the French conquered the Ligurian Republic, and its territory was divided over the departments of Marengo, Montenotte and Stura.

The department was subdivided into the following arrondissements and cantons (situation in 1805):[1] Its population in 1805 was 310,459.