Warburton skippered his country at the recent World Cup following injury to Matthew Rees and was a central figure in their charge to a first global semi-final since 1987.
The Cardiff Blues openside saw his tournament come to a premature end when he was sent off in the early stages of the last-four defeat to France but the manner in which he handled himself under intense media scrutiny following his dismissal won him further plaudits across the world.
Warburton collected the prestigious Pat Marshall Memorial Award from last year's winner Maggie Alphonsi at a dinner in London on Monday night after topping a poll ahead of former Lions boss Graham Henry, double Lions tourist Shane Williams and France captain Thierry Dusautoir.
"Sam has had an exemplary year, leading Wales with great dignity, marking himself out as one of the leading candidates to captain the Lions in 2013," said RUWC chairman Paul Morgan.
"He's a worthy recipient of the Pat Marshall Trophy, just beating Graham Henry in a poll of rugby media. He joins an illustrious list of winners."