Rigoberto Riasco (11 January 1953 – 29 August 2022) also known as "Little Poison", was a Panamanian professional boxer who competed from 1968 to 1982.
Riasco defeated such men as Dong Kyun Yum, Leonel Hernández, Rafael Ortega, Waruinge Nakayama, Luis Ávila, Santos Luis Rivera, Seiji "Flipper" Uehara, and Sanjo Takemori.
Riasco made his professional debut on 25 August 1968 with a four-round draw with Carlos Mendoza and after winning the featherweight national championship, he fought Alexis Argüello, who defeated him with a second round technical knockout.
Those victories earned him the chance to fight for the newly created WBC championship belt.
On 3 April 1976, Riasco defeated Kenyan Waruinge Nakayama for the WBC and Lineal Super bantamweight titles.