Hundreds of thousands of children are set to discover whether they have won a place at their first choice of secondary school.
Councils across England are sending out letters to about half a million families informing them of the school their child has been allocated for this September.
But thousands are set to be disappointed as competition for the best schools is fierce, particularly in big cities such as London.
Last year nearly one in six children in England failed to gain a place at their first choice secondary school, according to Government figures.
Results for applications by more than half a million children showed 83.2% were offered a place at their preferred school in 2010, resulting in a refusal rate of 16.8% - the same percentage as March 2009.
A small-scale snapshot survey conducted by the Press Association on Monday suggested that at least one in seven will miss out on their first choice this year.
The survey, based on responses from 30 English councils out of about 150 contacted, found that 13% of children will not get their preferred school. It also revealed sharp differences in acceptance rates around England.
In Manchester and Essex - one of the largest authorities - 83% of children have been given their first preference. In York this figure is 94.9% and in Devon it is 91.8%. However, just 60.2% of children in Westminster, central London, have been offered their first choice, while in Southend the figure is 61% - meaning in these areas two out of five children are not being offered their preferred school.
Schools Minister Nick Gibb said: "This is a stressful day for families as they wait to hear which school their child will attend, because the sad fact is there are not enough good schools delivering the academic standards demanded by parents."
The Government is introducing a range of measures to improve schools, behaviour and achievement, Mr Gibb said, which are designed "to give parents more genuine choice of a good school and to reduce the anxiety of finding a secondary school place".