The egg marks the latest encouraging development in the slow recovery of the endangered flying giants in the regions they historically inhabited. The effort has been hampered by hunters and lead poisoning of the birds.
A female released in 2004 in the Central California park and a male released the same year 30 miles west at Big Sur had been observed engaged in courtship behavior earlier this year, park spokesman Carl Brenner said.
"They are now the proud parents of a small egg," Brenner said.
Biologists confirmed the presence of the egg after hiking to the site on Friday.
In 1982, the last 22 California condors were placed in a captive breeding program. Today, there are 348 in the world, with about 180 flying free at three locations in California and at the Grand Canyon in Arizona. Another dozen are in Baja California.
The goal is to have 450 birds in three distinct populations, with 15 breeding pairs in each group.
"We had a good year last year in Southern California, but it's not universal because we had a number die of lead poisoning in the Pinnacles area and Central Coast," said Michael Woodbridge, a spokesman for the U.S. Fish and Wildlife Service Condor Recovery Program.
One of the dead birds was the mother of a male chick that eventually learned to fly in the wild last April on a ranch outside of Pinnacles National Monument. The chick survived and lives with its father.
Some birds suffer lead poisoning after eating gut piles left by hunters, despite a ban on lead bullets in condor country.