Miami's gleaming new condominiums and performing arts center get lots of attention. But its long-held aspiration to join the ranks of world-class cities may hinge on a less inviting, scruffier neighborhood: the newly named Health District.

Long known as the Civic Center, the district is the focus of a more than $1 billion effort by the University of Miami to build a clinical research institute, biomedical research labs, a hospital, and an enormous bioscience center over the next decade. The project has the potential to bring the high-wage jobs the city desperately needs but has lacked for years.

The idea is for the new facilities to build on the institutions already there -- Jackson Memorial Hospital, among them -- and create a cluster of health science research, testing and medical care to spin off and attract enterprises ranging from pharmaceutical companies to venture capital firms.

''The tendency is for start-ups to remain with the cluster that started it,'' said economist J. Antonio Villamil, who is doing an economic impact study of the Health District. ``This is a catalyst that could spark a lot of activity. It has tremendous possibilities from the point of view of the bioscience community and bringing in high-wage jobs.''

San Diego, for instance, evolved from a sleepy Navy base town to a dynamic bioscience center because of the Scripps Research Institute in nearby La Jolla, Villamil said. Scripps is also establishing a much-anticipated outpost in Palm Beach County, which some say could bookend with UM's efforts for a strong regional bioscience sector.

''The more the better,'' said Scripps spokesman Keith McKeown, when asked about UM's efforts. Scripps already inked a deal with UM so scientists at each institution can collaborate more easily.

But whether Miami can repeat the success of a city like San Diego remains an open question.

Miami still ranks among the poorest cities in the country, and the affordability gap grew during the recent real estate boom. And cities across the country -- such as Boston -- have well-established health science clusters that remain fiercely competitive.

Miami also has a history of poor planning and grand plans gone awry -- and it will take sound planning, strong leadership and time to establish a real biotech hub that creates and attracts businesses.

''Doing something like this will create immediate jobs,'' said Susan Webster, director of intellectual property management at Florida International University. ``But whether it will lead to economic development is another matter.''

Yet UM's plans are ambitious. If everything is built, it would result in more research space than the Scripps Florida project. The difference is that UM is building into the sky on a smaller footprint in an urban environment, while Scripps will sit on a sprawling 100-acre campus. UM has announced plans for 3 million square feet of projects in eight buildings.

UM has nearly completed its Clinical Research Institute and started construction on the Biomedical Research Institute. Over the next five years, it plans to complete a hospital and a large parking garage. The four projects are expected to create about 1,000 new jobs with an average annual salary of more than $60,000.

After that, UM plans a massive Bioscience Center and three lab research sites proposed to deliver about 5,000 jobs. The Bioscience Center deal depends on a land swap with the Camillus House homeless shelter that requires government approval. The shelter intends to move next door to the UM facility.

Already, residential and commercial developers are targeting the area because of the promise of UM's plans and the presence of everything from Miami-Dade State Attorney's Office to Jackson Memorial and Cedars Medical Center.

One development group is trying to win approval for a high-rise on the site of a Days Inn hotel next to UM's Clinical Research Institute. Called Civica Towers, it would include a 29-story hotel and 18-story medical office building. A host of other condo projects are proposed nearby.

Meanwhile, city leaders are promising a makeover of the neighborhood, which is pinched between I-95 and the Dolphin Expressway. Proposals include sidewalk repairs, better signs and changes to the Metrorail and bus stops to improve an area that has long been a tangled and unsightly mess.

Miami Mayor Manny Diaz, along with UM President Donna Shalala, co-chairs The Miami Partnership, an organization overseeing the Health District's redevelopment. Diaz plans to have a streetcar running from downtown to the Health District by 2010, although many hurdles remain.

Said Diaz: ``I think this is probably the single-most important economic project we have for long-term economic growth and sustainability in the city. Period.''