Although the official results will be declared only on Thursday, all exit polls predicted that Mr Modi was set to lead the Bharatiya Janata Party (BJP) to a landslide victory.
The Ananda Bazar Patrika-Nielsen survey gave 116 of the total 182 seats to the BJP. The Congress was placed a distant second with 60 seats.
C voters (Centre for Voting Opinion and Trends in Election Research) agency said Mr Modi could bag up to 124 seats. It put 54 seats in the Congress kitty.
The News 24 Today Chanakya poll predicted a much higher 140 seats for the BJP and 40 to the Congress.
A supremely confident Mr Modi, who has ruled Gujarat since 2001, gave a broad smile and flashed a V-sign with both hands after casting his ballot in his constituency Maninagar.
"The people of Gujarat will vote the BJP to power for a third consecutive term," he told the media triumphantly.
The Election Commission put Monday's voting percentage in 95 constituencies at 70.2 percent -- higher than the 64.39 percent recorded in 1995. Gujarat has 37.8 million voters.
The first round of polling in 87 constituencies on December 13 also drew 70.75 percentage of the voters.
BJP's Rajya Sabha MP Parshottam Rupala told IANS: "We will win, and we will better our record of 2007." Five years ago, the BJP bagged 117 seats while the Congress got 59.
His colleague Smriti Irani called the heavy polling "a victory for development" and warned that the expected Congress rout would be a defeat for "dynastic politics".
Actor-politician Irani was referring to Congress President Sonia Gandhi and her son Rahul who spearheaded their party's election campaign, repeatedly targetting Mr Modi on a variety of counts.
Congress leader Girija Vyas, however, asserted that Mr Modi would lose this time. "People have voted in large numbers and they have voted for change. We are sure the Congress will win."
Political pundits, however, seemed to agree broadly with exit poll predictions that Mr Modi was set to get another five years -- a result which could cast a shadow on national politics ahead of the 2014 Lok Sabha battle.
Pollster G.V.L. Narasimha Rao told a news channel that he expected a Modi wave.
In an undisguised comment on the Congress, political analyst Yogendra Yadav said the BJP was set to win due to "TINA (There Is No Alternative) factor".
Monday's polling -- like the first round -- was mostly peaceful, with millions of men and women thronging 23,318 polling centres in Kutch, north Gujarat and central Gujarat regions.
Narmada district recorded the highest voting -- 82.17 percent.
The BJP contested all 182 seats. Both exit polls and pundits appeared to agree that former BJP chief minister Keshubhai Patel's Gujarat Parivartan Party (GPP) had not hurt the BJP as feared.
The Election Commission said 5,573 of the voters Monday were over 100 years old.