BUENOS AIRES, Argentina — Cristina Fernández was sworn in yesterday as Argentina’s first elected female president, completing a rare husband-wife transfer of power that the nation hopes will ensure continued recovery from an economic meltdown.

Ms. Fernández, whose husband Nestor Kirchner is credited with leading Argentina out of its 2001–2002 economic meltdown, vowed to increase his center-left economic programs, create jobs, and reduce high poverty levels.

During her hour-long inaugural speech, Ms. Fernández’s voice rose in anger as she demanded faster progress from dozens of slow-moving court investigations of human-rights abuses of the country’s 1976–83 dictatorship. “I expect that in the four years of my term, trials that have been delayed more than 30 years will be concluded. We must try and punish those who were responsible for the greatest genocide” in modern Argentine history, Ms. Fernández, 54, told a packed Congress after taking up the blue-and-white sash from Mr. Kirchner, who gingerly adjusted it on her shoulders. Nearly 13,000 people are officially listed as missing or dead under a “dirty war” crackdown on dissent by past military governments. Activists estimate nearly double that number died. Ms. Fernández, who has been compared to Senator Clinton, embarks on a four-year term whose main challenge will be to prolong an economic recovery that has seen annual growth rates above 8% in recent years.

“I believe we have regained our balance,” Ms. Fernández said, recalling how her husband took office in May 2003 amid a debt default and a searing devaluation that was Argentina’s worst economic crisis in history. “In four and a half years this president — together with all Argentines — was able to change the scenario we were facing.”

She vowed to strengthen Argentina’s oft-criticized justice system, overhaul a poorly funded system of public schools and tackle rampant crime and a looming energy crisis. Several South American presidents looked on and thousands of supporters outside Congress waved blue-and-white Argentine flags. Ms. Fernández, a three-term senator who won office handily on a left-leaning ticket, captured 45% of the vote against a divided opposition Oct. 28. She joins Michelle Bachelet in Chile as the second sitting female president in South America.

Approval ratings for Mr. Kirchner topping 60% have been largely credited with Ms. Fernández’s victory, although she was praised for an astute, unorthodox campaign. Refusing to debate any of her rivals and granting few interviews, Ms. Fernández preferred to be photographed overseas meeting world leaders — projecting a flair for diplomacy while masking a lack of executive branch experience. Argentine law prevents more than two consecutive terms, but a husband-and-wife team could alternate in power for as long as their support continues. Ms. Fernández seems unlikely to alter Mr. Kirchner’s alliance with Latin American leftists such as President Chavez of Venezuela, but she could forge better ties with the next American president.

At home, the new president will try to cure some lingering headaches from the Kirchner term: inflation that private economists estimate in the double digits, corruption scandals, and a long-sputtering energy crisis.