Fidel Castro is not the head of the ruling Communist Party. In fact, he hasn't been party leader—or held any official positions—since 2006, he said in a column published today. After having surgery for intestinal bleeding that year, Castro issued a statement saying he was temporarily ceding power to brother Raul. But today he wrote, "I resigned without hesitation all my state and political positions, even that of First Secretary of the Party, when I got sick, and I never tried to exercise them after the proclamation of July 31, 2006."
Raul Castro didn't officially become president until February 2008, notes Reuters, which adds that Raul has reportedly taken over the role of party leader, too, and will likely keep it following next month's party congress.