A Manhattan cabbie made a shocking discovery when he opened a black suitcase that had been left in his taxi, police said Monday.

“He opened the suitcase and discovered it contained multiple sealed bags of heroin,” a police spokesman said.

The 63-year-old hack was around 34th Street and 11th Avenue at about 8:30 p.m. Thursday when he found the mysterious bag.

He opened it up to discover eight bricks of the illicit drug, police sources said.

The driver handed the drugs in at the 10th Precinct Station House in Chelsea, police said.