He also said the top challenges facing his successor would be Iran's nuclear ambitions and Mexico's drug-related violence, the Los Angeles Times reported Friday.
"These techniques worked," Hayden said of the agency's interrogation program during a farewell news conference. Methods such as waterboarding, which simulates drowning, have come under fire by human rights groups and President-elect Barack Obama as constituting torture.
Hayden, credited with restoring stability and morale during more than two years as CIA director, said the agency stopped waterboarding more than five years ago.
The outgoing director said he warned the incoming administration against going overboard in dismantling the agency's controversial counterterrorism programs. Obama has nominated Washington veteran Leon Panetta to be his CIA director.
"One needs to be very careful" about eliminating CIA authorities, Hayden told reporters, because "if you create barriers to doing things ... there's no wink, no nod, no secret handshake. We won't do it."
Concerning threats facing the next CIA director, Hayden said Iran is "getting close to a decision" on its nuclear program because the country is paying a heavy financial and diplomatic price for its efforts. The financial cost has grown as oil prices have fallen, he added.
Hayden also warned of the growing drug violence in Mexico, indicating U.S. intelligence officials have made new attempts to form counter-narcotics partnerships with the Mexican government.