Giancarlo Carlos (Martinez) Alvarado (born January 24, 1978) is a Puerto Rican professional baseball pitcher.

He remained in the Pirates system through 2001, playing with the Lynchburg Hillcats and AA Altoona Curve.

Unable to land a job in the affiliated minors after the 2003 season, Alvarado pitched for the independent Lancaster Barnstormers and Newark Bears, the Macoto Cobras in Taiwan and a couple of Mexican League teams during 2004–2005.

In 2009–10 off season, Alvarado signed with Japan's Central League side Hiroshima Toyo Carp.

[3] Alvarado signed a minor league contract with the New York Mets Organization on June 6, 2013, and was being assigned to the Las Vegas 51s, their AAA team.