The Benedict Cumberbatch drama took the top three spots between January and April, new figures released by the BBC reveal.
Series two premiere 'A Scandal in Belgravia' starring actress Lara Pulver in much-publicised nude scenes was the most-watched episode overall, with 2.5m viewers.
Finale 'The Reichenbach Fall' managed 1.9m.
'The Hounds of Baskerville' took the third spot with 1.6m, ahead of the Top Gear India Special which attracted 1.1m.
Other shows to make the top ten include the New Year's Day instalment of EastEnders (1.09m), the Hustle series eight premiere (967,000), the first part of the BBC's Birdsong adaptation (866,000) and the first episode of hit drama Call the Midwife (800,000).
Sherlock's Steven Moffat recently confirmed to Digital Spy that new episodes will begin filming in January, while series co-creator Mark Gatiss also revealed to DS that he will write the show's third series premiere.
