Two-thirds of parents believe Sats are a waste of time and that they put their children under unnecessary stress, according to a new survey.
The poll of more than 1,000 parents found that one in five also said they were unhappy with the curriculum at their children's school.
And the parents did not stop there. One in four said they had little or no faith in the ability of their children's teacher.
Christine Blower, acting general secretary of the National Union of Teachers, was unsurprised at the parents' opinion of Sats. "Parents see Sats as dangerous," she said. "They are extensions of exams right into the depths of childhood. And they don't take into account the individuality of each child."
Most parents surveyed believed that the curriculum did not engage their children sufficiently. But others worried that too much attention was being paid to the over- and under-achievers, at the expense of those in the middle.
Chris Davis, of the National Primary Headteachers' Association, acknowledged that many teachers gave attention to pupils whose improvement could make a difference to overall test scores.
"Every child is entitled to an equal amount of teacher attention, regardless of where they fall in the achievement spectrum," he said.
"Sats have narrowed the curriculum. They don't tell you much about children as a whole or their overall ability. The whole thing is pretty indefensible."
Key stage tests suffered heavy and on-going criticism this summer after tens of thousands of pupils' scripts were not marked on time and markers complained of shambolic administration.
But the parents, surveyed by online information network iVillage, did not reserve their criticism just for Sats and the curriculum. One quarter of them were either uncertain of the teacher's competence, or convinced that they did not have the ability to teach properly. In contrast, a survey carried out this year by the Healthcare Commission reported that, in some areas, fewer than six in 10 patients had trust and confidence in their GPs. In other areas, nine out of 10 patients trusted their doctors.
But Mr Davis insisted that teachers should not be worried. "This glass is three-quarters full, rather than a quarter empty," he said.
"It's inevitable that some children are going to be unhappy with their teachers. But it's only the extremes - the bad or very good teachers - that parents get to hear about."
According to the survey, almost a third of parents felt sad, anxious or fearful about their child's return to school this term.
A third feared that their children were not popular enough. And almost two-thirds said their children had been bullied at school.
In more than half of these cases, they added that the school had not done enough to address this situation.
Chris Cloke, head of child protection at the National Society for the Prevention of Cruelty to Children, said: "The start of new term can be very unsettling, so it's natural for parents to feel concerned. But bullying can only be beaten if there is co-operation from both teachers and parents."