The detentions are part of an escalating crackdown on the Brotherhood, Egypt's most powerful opposition group, ahead of the elections on April 8, and took place in the provinces of Giza, Sharkia, Menoufia, Beheira and Assiut.
At least three of the detained were leading members, according to the Brotherhood.
The Brotherhood says the state has systematically blocked its members from registering to stand for the April ballot through waves of arrests targeting likely candidates, bureaucratic obstruction and police harassment.
The Interior Ministry has declined to comment on the allegations.
The Brotherhood said that as of Monday, only 50 or 60 of its members had been able to submit papers to stand as candidates, but added that even that is no guarantee their names would appear on the ballots.
Egypt's local councils hold little real power, but seats may be important nationally if the Brotherhood wants to qualify to field an independent candidate for the presidency in the future.
Independent presidential candidates need support from 140 members of local councils in addition to backing from members of parliament.
Egyptian police routinely hold opposition politicians ahead of elections to prevent them from campaigning. They usually free them without charges when the vote has been held.
In a separate incident on Tuesday, four student members of the Muslim Brotherhood at Alexandria University were injured in clashes with campus security. They were protesting over what they said was increasing harassment by security men at university gates.
The Brotherhood seeks an Islamic state through democratic means. The government calls it a banned organisation but allows it to operate within limits.
The authorities will not let the Brotherhood form an official political party, so members stand in elections as independents.
Egypt postponed local council elections for two years in 2006 after the Brotherhood performed better than expected in a parliamentary election in 2005.
Last Mod: 11 Mart 2008, 17:35