Diablo 3 is the first PC title to top US sales charts since StarCraft II two years ago, which market research firm NPD calls "a testament to the power of the Blizzard brand".
According to NPD's figures, overall game sales in May took a 28 per cent dip year-over-year, dropping from $718.9 million to $516.5 million.
Following behind Diablo in the sales figures is Rockstar's Max Payne 3, which according to analyst Michael Pachter on Twitter currently sports sales figures that are "less than 50% of L.A. Noire's".
NPD analyst Anita Frazier said of the May figures: "Diablo III is the top selling title for May, the first time since July 2010 that a PC-only game accomplished this feat. Since the game launched day and date through digital distribution as well, full sales of the title are some multiple of what is reflected in the retail sales.
"Starcraft II was the title that topped the best-seller list in July 2010, a testament to the power of the Blizzard brand in PC gaming."
10 best-selling games in the U.S. for May 2012
Max Payne 3
Tom Clancy's Ghost Recon: Future Soldier
Call of Duty: Modern Warfare 3
Sniper Elite V2
Just Dance 3