Nelson Diaz or Nelson Díaz may refer to:
Nelson Diaz (born 1948) is a United States lawyer who has been a Philadelphia city solicitor, a judge on the Philadelphia Court of Common Pleas, and General Counsel at the United States Department of Housing and Urban Development (HUD). He was mentioned as a possible HUD Secretary in the Obama Administration, before Obama announced that Shaun Donovan was his pick for the position. He is running for the Democratic nomination for Mayor of Philadelphia, Pennsylvania in the 2015 election.
Diaz grew up in public housing in Harlem, New York. He graduated from St. John's University in New York City with a B.S. in accounting in 1969, having worked his way through school. He earned a J.D. from Temple University in 1972 – the first Puerto Rican to receive that degree at that University.
Diaz served as a special assistant to Vice President Walter Mondale on a White House Fellowship in 1977. He was elected as a Judge of the Court of Common Pleas, First Judicial District of Pennsylvania, from 1981 to 1993, and was also a lecturer at the Temple University School of Law from 1983 to 1992. Bill Clinton appointed him HUD General Counsel in 1993, and he served in that position, under Secretary Henry Cisneros, throughout Clinton's first term. Diaz worked for Philadelphia Mayor John Street as the Philadelphia City Solicitor from December 2001 through January 2004.
Nelson Díaz Marmolejo (born 12 January 1942) is a Uruguayan football defender who played for Uruguay in the 1966 FIFA World Cup. He also played for C.A. Peñarol.
Nelson Díaz Blanco is a Cuban baseball umpire. He officiated in high level international tournaments, including the Summer Olympics, Pan American Games, and Baseball World Cup. Díaz defected from Cuba in 2009.
Díaz was named for Rocky Nelson. Díaz's father, Placido, was arrested by the Government of Cuba in 1962 for conspiring against Fidel Castro. The family then moved from Havana to Güira de Melena.
A baseball player in his teens, Díaz was not skilled enough to play in the Cuban National Series. During his 20s, he took a 45-day course at Escuela Rafael De La Paz on umpiring.
Díaz served as an umpire in the Cuban National Series for 26 years, becoming its director of umpires. He officiated in several high profile baseball competitions. His first major tournament was the 1991 Pan American Games. After calling a balk against the United States in a semifinal game against Puerto Rico, Díaz initiated a shoving match with United States manager Ron Polk, which lead to increased stature within Cuban baseball. He also officiated in the 1999 and 2007 Pan American Games, the 1999 Baltimore Orioles – Cuban national baseball team exhibition series, the 2001 Baseball World Cup, the 2006 World Baseball Classic (WBC), and the 2008 Summer Olympics.