A month after making his groundbreaking Olympic debut, Pistorius had a clear lead going around the bend, but Oliveira stormed home to beat the South African by 0.07 seconds.
Pistorius had come to the Paralympics hoping to go one better than the trio of golds he won in Beijing in 2008.
Next up for the South African is the 400 relay, and he'll be hoping to defend his titles in the 100 on Thursday and 400 on Saturday.
Last month, appearing alongside able-bodied athletes at the Olympics, Pistorius reached the 400 semifinals and the 1,600 relay final.
(Copyright 2012 by The Associated Press. All Rights Reserved.)