Steitz also won the Gairdner International Award in 2007 "for his studies on the structure and function of the ribosome which showed that the peptidyl transferase was an RNA catalyzed reaction, and for revealing the mechanism of inhibition of this function by antibiotics".
Steitz modtog også Gairdner International Award i 2007 "for sine studier af ribosomets struktur og funktion som viste at peptidyltransferase var en RNA-katalyseret reaktion, og for at kortlægge mekanismen bag inhiberingen af denne funktion med antibiotika".