He also said that an African-American child is about five times as likely as a white child to be sent to jail.
'Willingness and sacrifice'
|The NAACP is America's oldest civil rights organisation [AFP]
“But what is required to overcome today’s barriers is the same as was needed then. The same commitment. The same sense of urgency. The same sense of sacrifice. The same willingness to do our part for ourselves and one another that has always defined America at its best."
Obama is also seeking the backing of the NAACP and its members tp push through his domestic policiy platform, particulalrly health care.
"We will be the people at the end of the day who help make him do what he knows he should do,'' Benjamin Jealous, the NAACP president, told the Associated Press news agency.
"We will help create the room for [Obama] to fulfill, I think, his own aspirations for his presidency.''
Obama did not intend to introduce new programmes or policy, and according to White House officials, it was not an occasion to celebrate his history-making election campaign.
"I think the first speech to black America, the first speech to white America, the first speech to America was the inaugural address,'' Robert Gibbs, the White House spokesman, told reporters on Wednesday.
Every president since 1909 has visited the NAACP at least once - some more frequently than others.
George Bush, the former president, did not attend the first five meetings before eventually addressing the group in 2006.
Obama expanded his message of equal rights beyond the black communities.
He said many Americans still face discrimination.
Racism, he said, is felt "by African-American women paid less for doing the same work as colleagues of a different colour and gender. By Latinos made to feel unwelcome in their own country".
"By Muslim Americans viewed with suspicion for simply kneeling down to pray. By our gay brothers and sisters, still taunted, still attacked, still denied their rights.''
Obama also urged NAACP members to encourage their young people to
find new role models beyond sports or music.
"I want them aspiring to be scientists and engineers, doctors and teachers, not just ballers and rappers,'' Obama said.
"I want them aspiring to be a Supreme Court justice. I want them aspiring to be president of the United States."