Scrapping the 10-yearly national census could harm social science in the UK, a group of MPs has warned.
The government is looking into whether there are less costly alternatives, with a view to scrapping the next census in 2021.
But the MPs said other methods of data collection may not be adequate and might not be any cheaper.
The government said the census was outdated and a "more effective, less bureaucratic" survey was needed.
The last census, which took place in 2011, cost an estimated £480m.
In 2010 Cabinet Office Minister Francis Maude said: "There are, I believe, ways of doing this which will provide better, quicker information, more frequently and cheaper."
But the Science and Technology Committee said they were not convinced that alternative ways of collecting the data would be a cheaper option.
The MPs also raised concerns that social science in the UK would suffer if serious consideration was not given to how the data would be replaced and that any alternative may not be able to provide nationwide coverage like the census.
However, the MPs acknowledged there were a range of problems with the census in its current form, which is always at least two years out of date by the time the data is published.
Chair of the cross-party committee Andrew Miller said: "Ministers must think hard before they take the decision to scrap the census."
"The census has provided the UK with one of the richest collections of population data in the world.
"It is incredibly valuable to social researchers, charities and the public sector and a move to cancel the census on financial grounds may prove to be a costly mistake."
The Office for National Statistics is currently consulting on alternatives to the 2021 census and is expected to report its findings in 2014.
A Cabinet Office spokeswoman said: "The government believes that the census, in its current form, is outdated.
"We are supporting ONS' work to design a replacement which will allow for more effective, less bureaucratic collection of the information necessary for the operation of public services. We will keep Parliament informed about the progress of this work."