Pacquiao started his professional boxing career in 1995 at 106 pounds (Light flyweight) at the age of 16 with his best friends namely Ryan Diwa, Joel Alconvidas, Erick Alcantara, Christopher Hernandez and James Linatoc. His early fights usually took place in small venues and were shown on Vintage Sports' Blow by Blow evening boxing show (hosted by John Ray Betita). His professional debut was a four-round bout against Edmund Ignacio on January 22, 1995, which Pacquiao won via decision, becoming an instant star of the program.
His weight increased from 106 to 113 pounds before losing in his 12th bout against Rustico Torrecampo via a third round technical knockout (TKO). As well-known sportscaster Joaquin "Quinito" Henson observed, Pacquiao clearly had not made weight, so he was forced to use heavier gloves than Torrecampo, thereby putting Pacquiao at a disadvantage.
Shortly after the Torrecampo fight, Pacquiao settled at 112 pounds, winning the WBC Flyweight title over Chatchai Sasakul in the eighth round only to lose it in his second defense against Medgoen Singsurat, or Medgoen 3K Battery, via a third round knockout on a bout held at Nakhon Si Thammarat, Thailand. Technically, Pacquiao lost the belt at the scales by surpassing the required weight of 112 lb (51 kg).
Following his loss to Singsurat, Pacquiao gained weight anew, this time stopping at the super bantamweight division of 122 lb (55 kg) where he picked up the WBC International Super Bantamweight title, defending it five times before his next world title fight came.
Pacquiao's big break came on June 23, 2001, against IBF Super Bantamweight champion Lehlohonolo Ledwaba. Pacquiao stepped into the fight as a late replacement and won the fight by technical knockout to become the IBF Super Bantamweight champion on a bout held at MGM Grand, Las Vegas, Nevada. He defended this title four times and fought to a sixth round draw against Agapito Sanchez, in a bout which was stopped early after Pacquiao received a headbutt.