Iain Valentine, chief of the zoo’s Giant Panda Programme, said that Tian Tian’s hormone levels had returned to normal, indicating that she was not pregnant.
He added that there was no evidence of a miscarriage and that the panda was in ‘great health’.
Mr Valentine added: “Tian Tian’s hormone levels have now returned to normal, so we can confirm that she is no longer pregnant.
“All data gathered since conception took place pointed to a pregnant panda likely to carry to full term, sadly this did not happen.
“There is no evidence she has had a miscarriage, so late reabsorption of the foetus could have occurred.
“Although Tian Tian has not successfully given birth, it is important for her individual biology as a female giant panda and for the future of giant panda conservation across the globe that we tried.”
The panda’s due date passed earlier this month, raising doubts that Tian Tian would give birth to a cub.
Tian Tian was successfully inseminated last year - the first successful artificial insemination carried out on a giant panda in the UK - but lost the cub at late term.
The insemination process was repeated in April of this year, with the zoo confirming that the panda had conceived but was not technically pregnant.
Mr Valentine confirmed that the panda viewing area would be reopened, adding: “From today, we will be opening the outdoor viewing area of Tian Tian and Yang Guang’s enclosures.”
Pre-booking for the first week will not be required, he said.
Tian Tian and Yang Guang arrived in Scotland in December 2011, on loan from China, and will stay in Edinburgh Zoo for a decade.
The pair are the first giant pandas to live in the UK for 17 years.