The Men's 51 kg event at the 2010 South American Games had its quarterfinals held on March 23, the semifinals on March 25 and the final on March 27.

Gold	Silver	Bronze
Cei Avila  Colombia	Julião Henriques Neto  Brazil	Luis Caycho Davila  Peru Fernando Martinez  Argentina

	Quarterfinals				Semifinals				Final
					Luis Caycho Davila (PER)	2
					Cei Avila (COL)	19
									Cei Avila (COL)	13
									Julião Henriques Neto (BRA)	6
	Julião Henriques Neto (BRA)	6
	José Luis Meza (ECU)	1
					Julião Henriques Neto (BRA)	8
					Fernando Martinez (ARG)	2
	Fernando Martinez (ARG)	10
	Evier Hernandez (VEN)	7

• Report