The spot for The Enfield Haunting was broadcast on ITV on Saturday 25 April, during an episode of Britain’s Got Talent, and attracted 37 complaints to the Advertising Standards Authority.
Some people who complained said their children were distressed by the ad and all complained that it had been inappropriate scheduled during a family programme.
The text at the beginning of the ad said "Based on real life events", and promotes a show about a poltergeist which haunts a family home.
Scenes included a light bulb exploding, children looking scared under a blanket, and a woman saying "This is a house of death, for you."
The ad was approved by Clearcast with an ex-kids restriction, which meant it should not be shown around programmes that are likely to appeal to children.
When contacted by the ASA, ITV Broadcasting said the ad had been appropriately scheduled and that Britain’s Got Talent was not a programme that was commissioned principally for children.
It added that the ad was "mildly frightening" and was broadcast at 8.45pm when young children were likely to be in bed.
Sky said it ran the same content on its own Sky channels and used the same ex-kids restriction without an issue.
In its ruling, published this morning, the ASA said the ad breached the BCAP Code relating to children and scheduling of TV and radio ads.
According to the watchdog, broadcasters had a general responsibility to ensure that they exercised responsible judgement on the scheduling of ads and that they operated internal systems capable of identifying and avoiding unsuitable juxtapositions between advertising material and programmes, especially those that could distress or offend viewers.
The ASA ruled: "We considered that the ad could be distressing to younger children. We also noted that the ad was shown at a time which was likely to be close to the bedtime of the younger children watching, and that a number of the complainants had referred to their children having difficulty sleeping because they were frightened.
"We therefore concluded that the ad had been inappropriately scheduled."