The letter was sent to newspapers yesterday ahead of the BBC Trust meeting today to discuss whether it should host ads on BBC.com.
The letter was signed by 10 MPs and follows an Early Day Motion submitted by Labour MP Austin Mitchell. The letter, published today in the Daily Telegraph, was signed by Mitchell as well as nine other MPs, including the Conservatives' Peter Bottomley and the Liberal Democrat's Mike Hancock.
They have called on the trust to reconsider the ad scheme, which could risk the corporation's international reputation "for just a few million pounds".
The MPs are concerned that hosting ads on BBC.com would lead to accusations of impartiality in the broadcaster's output, and fear the measures would eventually lead to ads appearing on the BBC's domestic news and entertainment services.
They wrote: "Senior foreign correspondents have warned that taking adverts will diminish the BBC's reputation overseas, and by extension, Britain's -- particularly in the Arab world where suspicions of western corporate interests run high, the very region we should be seeking to grow our reputation.
"If adverts are accepted on the international website, how long before BBC management contemplates their appearance on World Service, on web pages accessed within Britain, on Radio Three, on CBeebies?"
In addition, the letter states that technology used to block ads appearing on licence fee payer screens is far from perfect. The BBC is to use geo IP-blocking technology, created by Quova, a technology that detects where the web user is logging on from and if an ad should be sent.
BBC executives have defended their measures, stating the proposed ads would be restricted to only a few sectors on BBC.com, including sport and technology, and that users in the UK would not be able to view the ads.
The BBC is making the move as a way of making up part of the shortfall in its licence fee settlement, which gave it less than it hoped for.
The British Internet Publishers Alliance has echoed the MP's calls and has said that ads on BBC.com would impact on the corporation's reputation for "impartiality and integrity".
However, Bipa, which represents News International, Trinity Mirror and Guardian Media Group, is also concerned that commercialisation of the BBC would take revenues away from its members, the BBC's commercial rivals.
A spokesperson for the Bipa said: "While such revenues might seem superficially attractive as a means of augmenting the licence fee, the collateral damage to the private sector would greatly exceed the benefit."
This article was first published on brandrepublic.com