Would-be Lotto millionaires can now choose their numbers on the internet, organiser Camelot has announced.
Camelot hopes the internet will make Lotto more accessible
Players can now pick and pay for their Lotto numbers for the Wednesday, Saturday and daily play draws by visiting the National Lottery website.
Camelot says the introduction of Lotto online will make the draws more accessible than ever before.
The initiative follows the launch earlier in the year of interactive scratchcards on the internet.
Players of Lotto online can pick their numbers for up to eight weeks in advance and tickets can be bought between 0600 and 2300 BST each day.
On draw days, numbers can be bought up to 1930 GMT, as with ordinary tickets.
Dianne Thompson, chief executive of Camelot, said the operator was confident the launch of Lotto on the internet would make the National Lottery games more popular.
She said: "It is an integral part of our programme to reinvigorate and broaden the appeal of the National Lottery through new media channels.
"We are anticipating significant sign up from consumers who may not have played Lotto before but are attracted by the convenience of playing over the internet."
With Lotto online, players need not even check their numbers - the system keeps tickets safe and prompts winners to claim their prizes when they log on to the site.
The new prompting technology could go some way towards solving the problem of unclaimed prizes.
In November, the owner of a £2.6m winning ticket, bought in Northumberland for the Lotto Extra draw of 10 May, missed their chance to claim their prize.
Winners have 180 days to claim prizes.
The largest ever unclaimed National Lottery win was more than £3m.
All unclaimed prizes go to National Lottery charities.
Winning Lotto online players will have prize money paid to them personally, into their National Lottery account or into their own bank account.
National Lottery sales, including scratchcards, stabilised at £85m a week for the first nine months of 2003 - nearly £40m more than when the lottery was launched in 1994.