Crowds across Mumbai were jubilant on hearing of the sentence
The only gunman captured alive after the 2008 Mumbai attacks has been sentenced to death by an Indian court.
Mohammed Ajmal Amir Qasab, a Pakistani citizen aged 22, was found guilty on Monday of many charges, including murder and waging war on India.
Sentencing Qasab, the judge said he could not be rehabilitated. Qasab has the right to appeal.
The attacks left 174 people dead, nine of them gunmen. Relations between India and Pakistan have still to recover.
India blamed Pakistan-based militant group Lashkar-e-Taiba for the attack.
After initial denials, Pakistan acknowledged the attacks had been partially planned on its territory and that Qasab was one of its citizens.
Judge ML Tahaliyani said "he should be hanged by the neck until he is dead", adding he had lost his right to "humanitarian treatment".
AT THE SCENE
Prachi Pinglay BBC News, Mumbai
The death sentence was a foregone conclusion. The judge said that "leniency cannot be shown" because "he was more than keen to attack India".
He was studiously deadpan when the verdict was handed down on Monday. But today Qasab was emotional. A police constable later said: "He asked for water. He was upset and crying."
Security to get into the court was extremely tight. Afterwards, lawyers and policemen expressed relief that they would no longer have to attend this specially-built courtroom in a jail.
Outside the court, there were crowds of people celebrating the sentence. Demonstrators held up placards saying, "hang him", and people set off firecrackers in jubilation.
The BBC's Prachi Pinglay, in the courtroom in Mumbai (Bombay), said Qasab shook his head when asked if he wanted to make a statement. He was later seen wiping his face and talking to a policeman.
Prosecuter Ujjwal Nikam appeared in front of the court smiling and giving the victory sign.
"I'm very happy with the judgement. I have been successful in my attempt to put a balm on the wounds of the victims," he said.
During the trial Qasab had been branded a "killing machine" and "cruelty incarnate" by the prosecution.
"Today's sentencing sends the message that keeping Qasab alive would be a crime in itself," Mr Nikam added as crowds outside the court chanted "victory to Hindustan".
Qasab's lawyer had called for leniency, saying his client had been brainwashed by a terrorist organisation and could be rehabilitated.
Media amass to hear sentencing
He said no decision had been made yet on whether to appeal against the sentence, the Associated Press news agency reported.
In India the death penalty is carried out by hanging, but it is rarely used and most death sentences are commuted to life imprisonment.
Only one person has been executed since 1995. A security guard was hanged in 2004 for the rape and murder of a schoolgirl.
The BBC's Soutik Biswas in Delhi said if Qasab decided to appeal, the legal process could take years.
Our correspondent said Qasab could, as a last resort, appeal to the president for clemency, which would take even more time.
'Mastermind' in custody
MOHAMMED AJMAL AMIR QASAB
Pakistani citizen from Punjab province
Reports say he received little education, and spent his youth alternating between labouring and petty crime
India says he was trained for Mumbai operation by Lashkar-e-Taiba group in a remote camp
Captured on camera at the Chhatrapati Shivaji Terminus, a slight figure in combat trousers and a sweatshirt, clutching an assault rifle
Prosecutors said he had confessed but his lawyers then said his statement had been coerced, and it was retracted
Qasab was the only attacker caught alive in the three-day assault by 10 gunmen on hotels, a railway station, a restaurant and a Jewish centre in Mumbai.
Late last year, Pakistan charged seven people in connection with the attacks, including the suspected mastermind Zaki-ur-Rehman Lakhvi, who is alleged to head the Pakistan-based militant group Lashkar-e-Taiba.
But progress with those charges has been slow partly because of legal technicalities in Pakistan, correspondents say.
In the US, an American man of Pakistani origin has pleaded guilty to scouting targets in Mumbai for the attacks.
David Coleman Headley is alleged to have made five extended trips to Mumbai between 2006 and 2008. India has said it will ask for access to Mr Headley in connection with the attacks.