The Office for National Statistics (ONS) said the two “illegal activities” had a combined impact of £10bn on gross domestic product (GDP) in 2009, calculated at current prices.
In comparison, it said only £4bn, some 60% less, was spent on “own-account construction”.
The ONS defines own-account construction as “the production of new dwellings and major repairs and improvements by enterprises and households for their own use”.
Of the £10bn estimate, around £5.3bn was attributed to prostitution and at least £4.4bn to the illicit drugs trade.
A small estimate error was factored into the figures.
The ONS has published the data ahead of National Accounts due to be released in September, which will include latest figures for both enterprises.
It said the £10bn amount for drugs and prostitution is based on a variety of sources and assumptions.
It added: “The new estimates cover the import, production and sale of illegal drugs and the provision of prostitution services.”
The ONS said that between 1997 and 2009 the annual impact of drugs and prostitution varied annually between £7bn and £11bn, measured at today’s prices.