A court in India's western city of Mumbai (Bombay) has found a man guilty of planting one of the bombs in a series of attacks in the city in 1993.
Mohammed Ghansar placed explosives in a scooter near a market, the judge ruled. The blast killed 17 people. Ghansar could now face the death penalty.
He is among 123 defendants facing trial over 12 blasts that killed 257 people.
The attacks were allegedly ordered by the Muslim-dominated underworld in retaliation for Hindu-Muslim riots.
Ghansar had been charged on 14 counts. He was convicted in connection with the attack on the crowded Zaveri Bazaar.
The charge that he helped carry ammunition and facilitated the escape from India of one of the main defendants, Tiger Memon, was rejected.
Hundreds of witnesses
On Tuesday the court convicted four members of the Memon family over their roles in the blasts, which left more than 700 people wounded.
Verdicts are being announced in stages over the next few weeks and sentences have yet to be passed.
1993 MUMBAI BLASTS
123 arrested and tried
686 witnesses testify
35,000 pages of evidence submitted
13 years to reach verdict
The man thought to have masterminded of the plot, underworld don Dawood Ibrahim, has still not been caught.
India says he and Tiger Memon are hiding in Pakistan, a charge Pakistan has denied.
Bollywood star Sanjay Dutt is also among the accused.
Dutt was arrested 13 years ago on terrorism charges and spent nearly two years in jail before the Supreme Court ordered his release on bail.
The BBC's Zubair Ahmed in Mumbai says there have been few trials in India's legal history to match this one.
Evidence has been taken from more than 600 witnesses.
The bombings are believed to have been carried out by one of the city's notorious underworld crime syndicates, which were then dominated by Muslims.
Their motive is said to have been revenge for religious riots that left more than 2,000 people dead across India, most of them Muslims.
Most of the accused have been languishing in jail for the past 13 years. Lawyers have criticised the length of the trial.
The case has taken so long that 12 of the accused have died and others have been imprisoned for so much longer than their likely sentence that a guilty verdict may still result in them walking free.