Britain's Official Charts Company, which tracks music sales in the U.K., said Wednesday that the late artist's album overtook James Blunt's 2005 debut album to claim the title this week.
Winehouse's second album had jumped to the No. 1 spot on the charts shortly after the soul singer was found dead in her London house on July 23.
An initial post-mortem failed to determine cause of death. The singer's family said Tuesday that toxicology tests showed Winehouse had no illegal drugs in her system at the time of her death.
An inquest into Winehouse's death begins in October.
The Associated Press contributed to this report.