Miami is one of the most important financial centers. It is the major center of regional commerce, and boasts a strong international business community. According to the ranking of world cities undertaken by the Globalization and World Cities Study Group & Network (GaWC) and based on the level of presence of global corporate service organizations, Miami is considered a "Gamma World City."

Because of its proximity to Latin America, Miami serves as the headquarters of Latin American operations for over 1400 multinational corporations, including American Airlines, Cisco, Disney, Exxon, FedEx, Microsoft, Oracle, SBC Communications and Sony. Several large companies are headquartered in or around Miami, including but not limited to: Alienware, AutoNation, Bacardi, Brightstar Corporation, Burger King, Carnival Cruise Lines, Citrix Systems, DHL, Norwegian Cruise Lines, Royal Caribbean Cruise Lines, Ryder Systems, and Spirit Airlines. Miami International Airport and the Port of Miami are among the nation's busiest ports of entry, especially for cargo from South America and the Caribbean. Additionally, downtown Miami has the largest concentration of international banks in the country. Miami was also the host city of the 2003 Free Trade Area of the Americas negotiations, and is one of the leading candidates to become the trading bloc's headquarters. This effort has been guided by Florida FTAA.

Tourism is also an important industry: the beaches of Greater Miami draw visitors from across the country and around the world, and the Art Deco nightclub district in South Beach (in Miami Beach) is widely regarded as one of the most glamorous in the world. However, it is important to note that Miami Beach is not a part of the city of Miami. Even major TV networks sometimes forget this, as when Good Morning America visited Miami Beach and Charles Gibson thanked the mayor of Miami (but he was standing next to the mayor of Miami Beach).

In addition to these roles, Miami is also an industrial center, especially for stone quarrying and warehousing.

Miami is the home to the National Hurricane Center and the headquarters of the United States Southern Command, responsible for military operations in Central and South America.

Miami has also served as host venue for legendary legal proceedings, most notably the astounding $145 Billion verdict leveled against the nation's 5 largest cigarette manufacturers. This case was a class action on behalf of all afflicted Florida smokers and their families, represented by a prominent and successful Miami-raised husband and wife legal team, Stanley and Susan Rosenblatt.

According to the U.S. Census Bureau 2002 American Community Survey, Miami was the poorest city in the United States, with 31% of the residents having incomes below the federal poverty line. In 2004, Miami moved to third in the rankings ahead of Detroit, Michigan and El Paso, Texas.

Miami is also one of the least affordable places to live, with 69% of its residents spending at least 42.8% of their household income on home ownership. Miami ranks first among least affordable cities for home ownership.

As of 2005, the Miami area is witnessing its largest real estate boom since the 1920s. The newly created Midtown Miami, having well over a hundred approved construction projects is an example of this.