Grandmaster Flash gave his prized Technics turntable. Ice-T offered vintage tour T-shirts and rare CD's. Afrika Bambaataa gave a trove of jackets, caps and jewelry in his trademark Afrocentric style.

All will go to the Smithsonian Institution's National Museum of American History in Washington, where they will reside alongside the flag that inspired "The Star-Spangled Banner" and the Woolworth's lunch counter from Greensboro, N.C., where four black students sat for civil rights in 1960.

At an emotional and at times rowdy news conference yesterday at the Hilton New York, a group of hip-hop pioneers gathered beside the dark-suited, white-gloved Smithsonian staff to announce a plan for a major new collection devoted to the music. Called "Hip-Hop Won't Stop: The Beat, the Rhymes, the Life," it is to be a broad sampling of memorabilia, from boomboxes and vinyl albums to handwritten lyrics and painted jeans jackets, as well as multimedia exhibits and oral histories.

"Now whenever anybody asks me about my music," Ice-T said, he would direct him — with a torrent of blunt epithets — "to the museum."

Brent D. Glass, the director of the museum, said the project was begun in recent months with seed money from Universal Records and was still in its earliest stages of planning. But he said that he and his curators believed the time had come to recognize hip-hop, with its straight-from-the-gut raps and minimalist funk, as a significant cultural force that had spread all over the United States and, increasingly, the world.

"American music is the soundtrack to American history," Mr. Glass said. "Hip-hop has been a part of American music for more than 30 years."

With help from the music industry, the museum has been soliciting donations, and most of the initial contributors were present: in addition to Ice-T, Afrika Bambaataa and Grandmaster Flash, Russell Simmons, DJ Kool Herc and the dancer Crazy Legs have opened their archives, and were clearly proud of the recognition.

"Nobody expected this thing 35 years ago to be mentioned in the Smithsonian conversation," said Kool Herc, one of the prime technological innovators in the early days of hip-hop in the Bronx, who was still trying to decide what to donate.

The National Museum of American History is not the first major institution to collect hip-hop materials. The Experience Music Project in Seattle has also built a sizable collection, and in 1999 the Rock and Roll Hall of Fame in Cleveland organized an exhibition of hip-hop memorabilia that traveled to the Brooklyn Museum.

Mr. Simmons, the impresario who was a founder of the Def Jam label, said that at first he had feared that hip-hop's inclusion in a major museum would mean it had lost its power and novelty. His initial thought when contacted by the Smithsonian, he said, was "It must be over."

But in an opinion echoed by nearly every speaker, Mr. Simmons suggested that as hip-hop aged it was in danger of losing its connection to its roots and that younger fans and performers would profit from direct experience of the music's history. Hip-hop, he said, is "the only real description of the suffering of our people."

Museum officials say that the collection may take three to five years to develop and that they are still approaching musicians about donations. When complete, they say, the collection will be used for a long-term exhibition. The museum also plans scholarly symposiums to discuss the content, as well as a traveling show.

Afrika Bambaataa, who helped integrate hip-hop with electronic music in the early 1980's on recordings that remain influential, praised the museum in his familiar declamatory tone for its attention to "factology" in representing the music's history.

"Brothers and sisters," he said, "this is beautiful that the Smithsonian Institution is recognizing hip-hop culture for what it is."