Additional Sessions Judge Yogesh Khanna found the four men guilty under charges of gang rape, murder, attempt to murder the victim's male friend, unnatural offences, destruction of evidence and dacoity among other offences.
The quantum of sentence will be announced Wednesday, the judge said.
The four accused, held in jail since the crime was committed, were present in the court when the verdict was pronounced.
"I convict all the accused persons for gang rape, murder of helpless victim, attempt to kill complainant (victim's male friend), conspiracy, common intention, destruction of evidence....," the judge said while convicting the accused.
The accused face the maximum punishment of death in the case.
The court's verdict on Mukesh, Pawan Gupta, Vinay Sharma and Akshay Thakur came after almost nine months of the brutal crime in which the physiotherapy intern was gang raped in a moving bus.
Vinay Sharma began to cry on hearing the judgment.
The gory incident sparked nationwide protests and nudged the central government into enacting a stringent anti-rape law.
While one of the six original accused men was found dead in a cell in Delhi's Tihar jail, a juvenile involved in the crime was Aug 31 sent by the Juvenile Justice Board to a reform home for three years after it concluded that he was involved in rape and murder.
The incident occurred after the woman and her male companion boarded the bus in Munirka in south Delhi.
The six attackers on the bus threw both the physiotherapist intern and her male companion out of the vehicle -- without clothes -- on the street in the cold December night after committing the ghastly crime, police said.
The gang raped woman died of her injuries Dec 29 at Singapore's Mount Elizabeth Hospital, where she was airlifted for specialised treatment.
The gory attack sparked protests across the country with some people demanding the execution of the attackers and some calling for their chemical castration.
The charge sheet in the case was filed Jan 3 and the trial started Feb 5. The prosecution presented 85 witnesses and the defence 17.
Police said in the charge sheet the juvenile was the most brutal of all the accused.
Sensational rape cases that rocked Delhi post Dec 16
After the headline-grabbing Dec 16 gang rape last year, Delhi recorded over 1,000 rapes till Aug 15 this year. We list some of the more sensational ones:
- Dec 16, 2012: A 23-year-old physiotherapy student gang-raped by six people, including a juvenile, inside a moving bus in south Delhi.
- March 13, 2013: A seven-year-old girl raped inside a North Delhi Municipal corporation school in Mangolpuri.
- March 13: 17-year-old girl gang-raped by her four classmates in west Delhi's Bawana.
- April 15: A five-year-old girl abducted and repeatedly raped by her neighbour for two days in east Delhi's Gandhi Nagar.
- April 27: A six-year-old girl sexually assaulted in a public toilet and her private parts were mutilated with sharp object in west Delhi's Bawana.
- May 16: A 10-year-old girl raped by a tantrik in south Delhi's Govindpuri.