Rosendo Álvarez

On December 2, 1995, he traveled to Thailand and won the World Boxing Association strawweight title by close split decision over undefeated Thai champion Chana Porpaoin, who was 9-0 in title fights. In 1996, he defended his title three times including a third round knockout over future champion Kermin Guardia, a decision win over former champion Eric Chavez, and an eighth round knockout over undefeated prospect Takashi Shiohama. He had one bout in 1997, an eleventh round knockout over undefeated future interim champion Songkram Porpaoin (twin brother of Chana), for his fourth title defense.

In 1998, he fought to a draw with undefeated reigning WBC champ and pound-for-pound ranked Ricardo Lopez, dropping Lopez for the first and only time in his career. The fight was stopped in the 8th round when Lopez suffered a cut from a clash of heads, resulting in a technical draw on the scorecards. A rematch was set for later in the year, however, the fight was in jeopardy of taking place as Alvarez failed to make weight by 3 1/4 pounds. He was stripped of the title and the two met at an over the 105-pound strawweight limit, with the WBA title being on the line for Lopez only. Alvarez lost the rematch by a 12-round split decision, suffering his first loss as a professional.

Álvarez then moved up to the 108 lb division and won his following three fights, including a decision victory over future champion Tomás Rojas. On August 12, 2000, he lost by seventh round disqualification for repeated low blows to Beibis Mendoza for the vacant WBA light flyweight title. He later avenged this loss by twelve round split decision to claim the title. In his following fight, he faced Pichit Siriwat, who had previously defended the same WBA title five times before being stripped of it in 2000 for failing to defend it against Alvarez. He defeated Siriwat by 12th-round TKO. In 2003, he defeated Mendoza for a second time by decision and gained recognition as Ring light flyweight champion. Later that year, he fought to a twelve-round draw against then-IBF champ José Víctor Burgos in a unification bout. In 2004, he was stripped of his WBA and Ring light flyweight titles prior to a fourth meeting with Mendoza, due to his failure to make weight. He went on to win the fight by split decision.

On May 8, 2006, he challenged Jorge Arce for the interim WBC flyweight title, but was defeated by 6th round tko. After the fight, Álvarez was suspended by the Nevada Athletic Commission for the rest of 2006 and fined $2,000 because he failed a post-fight urinalysis. Álvarez tested positive for the banned diuretic Furosemide, also known as Lasix.

Álvarez is an influential promoter and manager in his native Nicaragua and it is assumed that the Arce fight was his last effort as a combatant.

In 2012, Álvarez returned to the ring at age 42, but lost by 5th round disqualification.