Trott, 24, went into the final points race boasting a 26-point lead after winning the flying lap to go with the elimination race and individual pursuit, having come second in the scratch race and the time trial too.
The most decorated woman in British Olympic history, who also won the team pursuit earlier in the Games, was never really troubled as she warded off any danger and picked up plenty of points in sprints.
Sarah Storey takes record 12th gold Paralympic medal
"I can’t believe it. I don’t want to cry," she told ther BBC, as she broke down in tears. "I did not expect that at all. I am so happy that it came together and can’t thank everyone at home that you don’t see enough.
Britain's Laura Trott holds up a flag as she celebrates after winning the Women's Omnium Points race
Image credit: AFP
"They really help me and I couldn’t have done it without everyone, especially Paul Manning my coach. He puts up with me on a daily basis and today I am literally over the moon.
You think of people like Sir Chris Hoy who have come and done it time and again, to repeat my success I can’t explain I am so, so, happy.
Parnter Jason Kenny won the Keirin to draw level with Sir Chris Hoy on six golds and one silver to become the joint most decorated British Olympian.
Trott set the second fastest time in the 500m time trial to lead on 156 points, ahead of Jolien D'Hoore (144) and Sarah Hammer (140).
Australia's Annette Edmondson set the fastest time in the time trial, and sits in fourth on 130 points.
Just two events stand between Trott and a fourth gold, with the flying lap and points race taking place at the velodrome tonight.
On Monday Trott, 24, finished second in the scratch race before winning the individual pursuit and elimination events.
The track programme concludes at the Rio velodrome on Tuesday when, as well as the omnium, the women's sprint and men's keirin will also be decided.
Britain have won four of the seven titles so far and could be set for more with Rebecca James and Katy Marchant both into the semi-finals of the sprint.
James is up against Elis Ligtlee of the Netherlands, who beat her to gold in the kierin, while Marchant faces twice world champion Kristina Voegel of Germany. Voegel, at 25, is the oldest of the four qualifiers, who have an average age of 23.
GB cycling boss defends gold-medal haul as questions are asked
Kenny wins crazy Keirin final to draw level with Hoy on record six golds