Answer
Román González's longest winning streak in professional boxing was 46 fights. This streak spanned from October 19, 2008, to February 27, 2015. During this time, González won 46 consecutive fights, including 42 by knockout. He won the WBA flyweight title in 2010, and defended it 11 times. He also won the WBC flyweight title in 2012, and defended it four times.