PASADENA, Calif. — The opening of a Scientology center in this city’s Old Town neighborhood was a significant local event. Church members spent $10 million to buy a historic four-story building and $6 million more to restore it to its 1906 luster before a gala dedication ceremony on July 18.

But the Pasadena project is just one part of a much larger undertaking for the church: the creation of about 50 new centers in 16 countries.

The global real estate firm CB Richard Ellis is managing the project on behalf of the church. Dana Barbera, a senior director of CB Richard Ellis, said the challenge facing his firm was that the church was seeking to install nearly identical facilities in buildings as distinctive as a resort near Johannesburg, a bank headquarters in Brussels and a hotel in Kaohsiung, Taiwan.

His project management team, working with the architecture firm Gensler, which is based in San Francisco, is inserting chapels, private counseling rooms and saunas for purification into each of the newly acquired buildings.

“We have larger clients, but I can’t think of another rollout of this complexity,” said Mr. Barbera, who is based in Los Angeles.

Instructions for the buildings, called “ideal orgs,” are derived from the writings of L. Ron Hubbard, the church’s founder, who died in 1986. According to a Scientology spokesman, Tommy Davis, Mr. Hubbard was “extremely specific” about how the buildings should be laid out. “There’s no interpretation involved,” he said, though he credited David Miscavige, the church’s leader, with driving the project.

This 2010 interview with cult spokesman Tommy Davis was among his last. He has since mysteriously disappeared.

Mr. Davis, a second-generation Scientologist, said the buildings, which must be at least 40,000 square feet, cost from $4 million to $20 million each, bringing the price of the current expansion to $500 million. In each case, he said, local parishioners raise money to buy and renovate the buildings.

Bob Wright, the church’s international construction supervisor, said the organization typically looked for buildings “with a presence” in places with significant pedestrian traffic. Those criteria often lead it to historic buildings. Choosing historic buildings gives the church, which was established in 1954, “legitimacy as an established, historical religion and not just some new invention,” said Hugh B. Urban, a professor at Ohio State University who has completed a new book on Scientology.

The property in Pasadena, known as the Braley Building, was built in 1906 as an auto showroom and is on the National Register of Historic Places. Its ground floor, which contains a cafe, a bookstore and a multipurpose room for community events, stays open until 10 p.m. On a recent Saturday, a worker stood on the street handing out cards that offered a free introduction to Mr. Hubbard’s philosophy, called Dianetics.

Whether the church’s current membership needs all these new buildings, or can sustain them, is an open question. Mr. Davis said membership is “in the millions,” with one third in the United States. But the American Religious Identification Survey found that the number of American Scientologists dropped to 25,000 in 2008 from 55,000 in 2001.

And the church has other problems. In recent years, Scientology has faced defections and accusations of abuse by former members. Professor Urban said that opening so many new centers “could be a marketing strategy to give the appearance that Scientology is in a period of massive growth, which would in turn attract people. That’s the kind of thing they’ve done, historically.”

But Mr. Davis said the church’s expansion project had a simple goal: “We are building the cathedrals of the future.”

In the next year, he said, the church expects to add centers in Minneapolis; Cincinnati and Columbus, Ohio; Sacramento, Inglewood and Santa Ana, Calif.; Tampa, Fla.; Portland, Ore.; Melbourne, Australia; Caracas, Venezuela; and Kaohsiung.

In some cases, the old buildings have outlived their original purposes and can be picked up at fire-sale prices. “We’re tough negotiators,” Mr. Wright said. He said that applies not only to the real estate but also to the contents of the buildings. “Say we’re doing 60 churches with 400 or 500 chairs per church. Can we get a good price?” he said. “The same with the saunas, the same with the carpets.” In the case of Pasadena, Mr. Davis said, parishioners wanted to have a building there, and they raised the money to make it happen. “They couldn’t have chosen a more expensive place than Old Town Pasadena. Not only that, but we bought at the top of the market.”

The church’s expansion in Pasadena has not been without hitches. The building was bought by a group of parishioners, which some saw as obscuring the purpose of the acquisition. But Mr. Davis said it was a common business practice for large organizations to buy properties without revealing their identities. “It has do with getting the best possible price,” he said.

The church was also criticized for leaving the Pasadena building vacant for almost two years before starting the renovation. “If you find just the right building, you’re going to snap it up if you can, even if you’re not ready to start construction right away,” Mr. Davis said.

Religious protests have been rarer, although a march in 2008 brought out about 30 opponents of the church, including a woman in a medical mask with a sign saying, “Scientology disconnects families,” and a man whose shirt said, “Scientology Kills,” according to an article in The Pasadena Weekly.

“The protesters are not a legitimate source of information about the Church of Scientology,” Mr. Davis said.

Paul Little, the head of the Pasadena Chamber of Commerce, said he had fielded calls from concerned members of the community. Some, he said, were simply worried that the church would proselytize in Pasadena. But, he said, the church is a longtime member of the chamber, and “our job is to support our members. We don’t go judging their beliefs.”

In the Old Town neighborhood, some business owners were concerned that giving over a large building to a noncommercial use would diminish foot traffic to adjacent stores and restaurants, Mr. Little said.

Though the styles of the Scientology buildings vary — many of the details in Pasadena reflect that city’s Arts and Crafts tradition — they share certain features, including elaborate signs made in a church-owned workshop in Los Angeles. Other common features of the churches are offices for Mr. Hubbard, set up as if he could arrive at any moment. “It’s a sign of respect,” Mr. Davis said.

Mr. Barbera said that CB Richard Ellis, which has 2,500 employees in its global project management division, is handling everything from contract negotiations to construction management. CB Richard Ellis began became the exclusive project manager in 2009. Mr. Barbera said the church employees he had worked with were “very old school. They pay their bills. They work hard, and they expect to get a lot done.”

Donna Taliercio, a spokeswoman for Gensler, said the architecture firm, which is based in San Francisco, began working with the church in 2005. It has completed 10 projects, she said, and has several more under way. She said Gensler had teams in three offices — Atlanta, Los Angeles and San Francisco — working on Scientology projects.

One of those employees is Irwin Miller, who served as design principal on the Pasadena project. Mr. Miller, who has a master’s degree from the Graduate School of Design at Harvard, said he was a “Jewish kid from Boston” who enjoyed working for the church, because it gave him a chance to “tackle important civic projects.” The new Scientology buildings, he said, “are helping to revitalize the urban landscape.”