She won Sunday's presidential run-off election with 56% of the vote to rival Jose Serra's 44%.
Ms Rousseff takes office on 1 January next year when President Lula steps down after completing the constitutional limit of two consecutive terms. Her election as the country's first female leader was a sign of the democratic progress Brazil had made, Ms Rousseff said in her victory speech in the capital, Brasilia. "So I am here stating my first post-election commitment: to honour Brazilian women so that this fact - unprecedented until now - becomes something normal and can be repeated and expanded in companies, public institutions, and organisations that are representative of our entire society”. She continued: "I would like very much today for fathers and mothers of daughters to look in their eyes and tell them: 'Yes, a woman can.'"
Ms Rousseff, a former Marxist rebel who was imprisoned for three years in the early 1970s for resisting military rule, promised to protect freedom of expression and worship, and to honour the constitution.