Marriott Corp. has mailed letters to its 48,000 individual stockholders, urging them to join and support a young Washington lobbying organization called Citizen's Choice.

Sponsored and intially financed by a $150,000 loan from the U.S. Chamber of Commerce, Citizen's Choice counts Marriott President J.W. Marriott Jr. among its 11-member board of directors, along with Eastern Air Lines Chairman Frank Borman and Pepsico Chairman Donald M. Kendall.

In his letter to "dear fellow share-holders," which has upset some of them, Marriott said that if they "are as interested as I am in stopping government intrustion in our private lives, you will want to review the attached material."

He described Citizen's Choice - which has offices in the U.S. Chamber building across Lafayette Park from the White House - as working "to stop government growth and support free enterprise."

Marriot said "the time has come to let Washington know exactly where we stand on the issues of bigger government, higher taxes and increased government regulation of our economic and personal freedoms . . . I urge you to join with me and thousands of other American citizens in a vital new movement which can truly hepl protect our mutual best interests."

According to Marriott spokeswoman Barbara H. Van Blarcum, the company's recent mailing cost it 12 cents a stockholder - a total of less than $6,000 which came out of the public relations budget.

She said response to date has been about 10 to 1 in favor of the letter, with most of the negative letters objecting to spending company money on such a project.

She is telling stockholders who object to Marriott's letter that the company president "regrets" their feelings butthat the mailing was completed "to enlist support for the cause of business in this country."

Van Blarcum said the expenditure is legal "but, even more importantly, [it is] a legitimate use of corporate funds. American business has both a right and a duty to guard its own interests just as unions use their funds, and government its franking privilege, to support variuos programs."

The decision to underwrite the mailings, an effort similar to direct mail distributions for Citizen's Cause by other companies or business gruops, was made by Marriott top management without prior approval from the broad of directors, she added.

Most of the cost of mailimg involved postage, with Marriott using bulk rates. The brochures on Citizen's Choice were provided by that organzation.

The mailing included material desribing the organization and membership applications. Dues range from $15 to $1,000. More than 500 Marriott stockholders have joined since receiving their letters, according to Van Blarcum. Marriott personally broke his long silence on national economic issues recently by attacking government regulation in a speech in St. Louis.

Citizen's Choice's "battle plan," described in an interview yesterday by Executive Vice President Thomas J. Donohue, is to concentrate on three areas: maintaining economic stability, "limiting government growth and intrusion" and "challenging unreasonable big union power."

Although a nonprofit group, Citizen's Choice is a registered lobbyist and its membership dues are not tax deductible. Donohue said that Citizen's Choice was formed about 15 months ago and now has close to 20,000 members. Its summer membership goal is 40,000.

"It was evident that the Chamber of Commerce was at a disadvantage, only expressing the views of business, when we were of the opinion that many people had strong feelings on the economy, government regulation and inflation," he said.

Citizen's Choice has borrowed its techniques from Common Cause, Ralph Nader and such groups as the Sierca Club in seeking "to affect Congress on public policy issues . . . from the people back home," according to Donohue, who also serves as an executive of two other Chamber of Commerce affiliates.

Donohue said Citizen's Choice will concentrate on gathering "grass roots" support for its positions rather than direct lobbying here, although there will be some congressional testimony. Members receive a monthly newsletter, participate in public opinion polls and are provided a "hot line" telephone service with reports on current legislation.

Citizen's Choice has a staff of less than a dozen and rents office space from the Chamber. The group is paying interest on its loan and hopes to begin repaying the actual loan this year. As membership grows, new funds will be devoted to marketing for additional members - partly through advertising.

"Congress has changed a lot" in the past decade. It has a faster turnover and citizens groups have more of an impact on decisions, Donohue stated. "We have on delusions of grandeur . . . we want to bring more and more people into the battle, to bring a sense of balance to government."

In its March newsletter. Citizen's Choice condemns President Carter's proposed $500 billion budget for fiscal 1979 as one that "ignores his campaign promises" and one that effectively abandons a commitment to balanced budgets. The group also opposes the proposed Labor Law Reform Bill, calling it legislation "that would make it mighty hard, if not impossible, for a union to lose any representation election."