Tanni Grey Thompson was edged out of the medals in her final race in Athens, but still finished the day as Britain's greatest ever Paralympian.
By Elizabeth Hudson
BBC Sport in Athens
She came fourth in the T54 200m, but had earlier won the T53 400m for an unprecedented 11th Paralympic gold medal and second in Athens.
"It's been an amazing and emotional Games for me," said the 35-year-old, who also won the 100m on Thursday.
"I don't think I have cried so much after my races."
Grey Thompson paid the price for a bad start in the T54 200m to narrowly miss out on bronze.
Chantal Petitclerc won her fifth gold of the Games in 28.95 seconds with Manuela Schaer of Switzerland second and American 15-year-old Tatyana
McFadden in third, just .06 of a second ahead of the Briton.
"Everyone left me at the start and although my first 100 was poor, my second 100 was superb and I gave it everything but I didn't know until I saw the screen if I had been third or fourth," she said.
"If I had a better start I could have won bronze but it would have been very difficult to beat Chantal as she is pushing so well here.
"It is a little frustrating for me as I had been starting well. I came into the Games thinking I could win two golds and medal in my other two events but I wouldn't swap my two golds for anything.
Grey Thompson had a superb start to the day when she secured a golden double in Athens, adding the T53 400m crown to her 100m title on Monday.
The Welsh racer started well and pushed on to beat Swede Madelene Nordlund and Italy's Francesca Porcellato in 57.36 seconds - a new Paralympic record.
The 35-year-old refused to be drawn on whether she would bring the curtain down on her illustrious career before Beijing in 2008.
"If you asked me now whether I would go through to Beijing in four years time, the answer would be yes but this is not the time or the place to make
a big decision like that," she said.
"It might be different when it is the depths of winter in Redcar, there is ice on the ground and I am going out for another session of winter training."