"The judgement itself is a message to Pakistan that they should not export terrorism to India," P Chidambaram, India's interior minister, said after the verdict was delivered.
The special court is expected to issue a sentence on Tuesday.
Al Jazeera's Prerna Suri, reporting from the court, in Mumbai's high-security Arthur Road Jail, said Kasab's team may appeal against the sentence if he is given the death penalty.
"Capital punishment in India is only awarded to the rarest of rare instances," she said.
"But the public prosecutor told me he will be demanding the death penalty tomorrow [Tuesday].
"There might be appeals which will go to the highest supreme court. He [Kasab] may also use the presidential mercy petition which is given to convicts in the country."
Security officials were on high alert as the court proceedings went ahead, setting up roadblocks around the court.
The interior ministry issued a statement urging citizens to avoid crowded places on Monday, while police have increased patrols throughout the city. Police and soldiers set up.
Kasab was reportedly arrested in a stolen car at a roadblock shortly after the 2008 attacks.
Prosecutors presented a range of evidence during his seven-month trial, including fingerprints, DNA evidence, security camera footage and photographs allegedly showing Kasab carrying an assault rifle.
Kasab first denied the charges, then pleaded guilty, before reversing his guilty plea, claiming he was set up by police.
On Monday, in court, he stood but did not react to a summary of the verdict read out to him in Hindi by the judge and then sat down.
Thirty-five other people had been named as "co-conspirators" in the case.
Seven of them, including a founder of the Pakistan-based group Lashkar-e-Taiba, are currently on trial in Pakistan.
India, blaming the group for masterminding the attacks, broke off peace talks with Pakistan.
Satish Jacob, a security analyst based in New Delhi, told Al Jazeera that the guilty verdict was expected.
"There is a great degree of emotion involved in this judgement, because [Kasab] is seen as a face of Lashkar-e-Taiba," he said.
"I talked to very senior Pakistani journalists in a summit in Bhutan and asked them about Kasab, and all of them said everyone in Pakistan knows Kasab was recruited by Lashkar."
The Pakistani government last month asked India to hand over Kasab and one of his co-defendants, but the Indian government has not responded to the request.