Thokozile Masipa said the Paralympian sprinter should report to Weskoppies Psychiatric Hospital in Pretoria as an outpatient each work day morning and remain there until 4:00pm.
He will be tested to see "whether he was capable of appreciating the wrongfulness of his act or acting in accordance with appreciation of the wrongfulness of his act," said Masipa.
Pistorius is accused of murdering 29-year-old model Reeva Steenkamp at his Pretoria home after a row. He says she was killed by accident after he mistook her for an intruder.
As an outpatient, Pistorius will not stay in the hospital and undergo 24-hour observation, but visit for his interviews and tests.
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The Paralympic gold medallist, nicknamed the "Blade Runner" for his prosthetic limbs, will be monitored by three psychiatrists and a psychologist.
The trial is postponed until June 30 while the athlete undergoes testing.
"We'll see you on the 30th of June at 9:30," said Masipa.
The psychiatrists' final report may drastically alter the direction of the trial.
During two months of trial, his lawyers have sought to portray him as manically obsessed with safety after a difficult childhood in which his fearful mother abused alcohol and in the face of high crime levels in South Africa.
The judge said a "proper inquiry" was needed to test whether Pistorius had a disorder that could mean he was not fully responsible for his actions.
If he is found to have diminished capacity it could have a large impact on any possible sentencing.
If he is found to be of sound mind then that would kick away a key pillar of his defence.