According the Kölner Stadt-Anzeiger, last year authorities confiscated nearly three tons of the stimulant drug, compared to 1.5 tons seized in 2009.
Amphetamines, an illegal recreational drug, are commonly found in many medications used to treat Attention Deficit Hyperactivity Disorder.
One side effect of amphetamine use is a loss of appetite, and the drugs have long been abused by some dieters.
Wolfgang Schmitz of the Cologne customs authority told the newspaper that the drugs are a "people's plague."
A special commission of customs investigators and police is currently investigating the largest amphetamine case in German criminal history, the paper said.