Ghosh's re-election came at a party meeting attended by around 700 of its state functionaries.
Amid shouts of 'Jai Sree Ram' and 'Bharat Mata ki Jai', Ghosh was garlanded by state leaders and handed the certificate of his election by party's national General Secretary Murlidhar Rao at the National Library auditorium.
Ghosh, also a Lok Sabha member, had filed his nomination for re-election as state President on Wednesday. His term will come to an end in 2023.
His re-election brings to an end all speculation about who would helm the party in next year's polls, in which the BJP is hoping to unseat the Trinamool Congress and come to power in a state where it had a weak presence even five years back.
Ghosh had taken over as the state party chief in December 2015, and piloted the BJP through the Assembly polls in 2016 before leading it to its best performance ever in last year's general elections when the saffron outfit bagged 18 Lok Sabha seats in Bengal.
A long-time Rashtriya Swayamsevak Sangh (RSS) pracharak, Ghosh was sent to the BJP in 2014, and made a state General Secretary.
All top party leaders in the state as well as central leaders Shiv Prakash and Arvind Menon were present at the meeting.
Speaking after his re-election, Ghosh thanked the party's crore members in the state for reposing faith in him, and reminded them that the society's expectations from the BJP have gone up.
He also remembered all the party workers killed in political violence in the state over the past few years.
"Today, I remember all the workers who have worked untiringly over the past four years, and taken the party to its present position.
"Ninety-two of those workers are no more with us. Dozens of party functionaries now cannot walk, having fractured their legs, hips... they are bedridden. At least 2,000 of our functionaries are in jail, while 3,000 have been rendered homeless. Their only crime is they worked for the BJP," he added.
( With inputs from IANS )