Lothian and Borders Police described the traffic at Straiton, near Loanhead, as "horrendous".
Despite earlier warnings, shoppers have flocked to the new store creating tailbacks as far as the Lothianburn junction of the Edinburgh bypass.
Interest reached fever pitch as shoppers rushed to get a taste of the Swedish furniture giant's first Scottish store.
Major traffic problems
The store had tried to dissuade people from turning up in the first two weeks in an attempt to avoid major traffic problems in the area.
To discourage car owners, the company has even offered free delivery to customers who arrive by bike or bus.
The lure of free vouchers worth £1,500 for the first customers when it opened on Thursday attracted several shoppers to camp outside the store's main entrance.
Sisters Elaine Barnes and Janice Tennant set up camp among the rubble as workmen added the finishing touches to the premises.
Elaine, 26, from Renfrew, said: "I thought it was too good an opportunity to miss so I asked my sister if she wanted to come with me as I didn't want to go on my own.
Free food
Ikea bosses allowed the sisters to use the store's toilet and shower facilities and provided them with free breakfast and lunches.
Janice, 23, from Clydebank, said: "I am unemployed at the moment so this will come in very handy."
Eagerly awaited
The arrival of Ikea is perhaps the most eagerly awaited store opening ever witnessed in Scotland.
Every week 15,000 Scots travel to Gateshead Ikea store. The firm has planned a store in Scotland for the last five years but has been held up by planning permission.
A second Scottish store is in the pipeline for Glasgow.
City of Edinburgh Council
IKEA
British Red Cross
The BBC is not responsible for the content of external internet sites.
Toys withdrawn in E.coli health scare
Collins calls it a day for Scots
(From Sport)
Pro-lifers plan shock launch
Death inquiry anaesthetist barred
Bowled over by Lord's
Ministers loosen purse strings
'Delight' at Tunnel court outcome
Derby double swoop fails
(From Sport)
Demands for far-reaching information bill
Gaelic makes sound use of the internet
Trusts 'ignoring' depression advice
BBC Scotland - On Air
'Little change' since poverty pledge
Nine hurt as bus crashes into pub
Teachers' union in pay body challenge
Dental death hearing adjourned
Parliament ponders Royal High flit
Reid quits PR job
Industry misses new trains target
Football and royalty dominate Westminster
The next Battle of Britain
(From Sport)
Man charged with murdering lab technician
Lockerbie trial judges named
Festival award for Ratcatcher