With almost 1,800 officers, the police took action on Thursday in five federal states against the rocker association "Bandidos".
They searched a total of 104 objects and seized weapons, ammunition and "large amounts of cash", said the Federal Ministry of the Interior in Berlin.
Interior Minister Horst Seehofer (CSU) ordered the raids because of "urgent suspicions" of criminal offenses.
The association strives for "a territorial and financial increase in power over competing rocker-like groups and enforces corresponding claims also by force," said the ministry.
The raids focused on North Rhine-Westphalia, but searches also took place in Lower Saxony, Hesse, Rhineland-Palatinate and Thuringia.
"The federal and state governments are using all means available to the rule of law to combat all forms of crime," said Seehofer.
The operations were directed against the group "Bandidos MC Federation West Central".
They were "trouble-free".
According to the Home Office, the group was founded in Houston, USA, in 1966. She has been represented in Germany since 1999. As a so-called “world club”, it now has branches in many countries. The official purpose of the "Bandidos MC Federation West Central" is the promotion of motorcycling together and the organization of events.