Mars served as both host and musical performer on the episode, which aired yesterday (October 20).
When asked on Friday (October 19) how he felt about his hosting duties, Mars said he felt he had "nothing to lose".
Deadline reports that the episode drew in a 5.4 overnight rating and 14 share in the metered-market households.
It is the show's highest rating since Lindsay Lohan hosted in March.
The episode featured a parody of the presidential debate between Mitt Romney and Barack Obama, as well as two live music performances from Mars.
Comedian Louis CK is set to host the programme on November 3, with musical guest Fun.
Watch Bruno Mars on Saturday Night Live below (US only):