The Equal Employment Opportunity Commission, in a decision it was ordered to suppress, found "patterns of sex, race and national origin discrimination at all levels" of Sears Roebuck and Co. and said there was reasonable cause to think the nation's largest retailer was violating federal law in 69 specific ways.

The asserted violations included "restricting blacks and Spanish-surnamed Americans to lower-paying, less desirable jobs"; "failing to hire blacks and/or Spanish-surnamed Americans" for jobs in certain stores "in proportion to their rate of application"; relegating women to lower-paying, less desirable jobs and in some cases paying women less than men and blacks less than "Anglos" for the same work.

The decision was ordered suppressed by the U.S. Circuit Court of Appeals here last year after Sears sued to prevent disclosure. Sears and the EEOC were then supposed to be negotiating over Sears' disputed employment practices.

Those negotiations recently broke down, and the EEOC is preparing to go public with its case against Sears by taking the company to court.

It was partly to blunt this expected onslaught that Sears filed its own heavily publicized suit against the EEOC and nine other civil rights and statistical agencies of the federal government last month.

In that suit and again in a separate statement yesterday, Sears vehemently denied the charge of discrimination. "We are proud of our record of affirmative action," the company said.

Sears' suit seeks to blame the federal government for having created an "lmbalanced civilian work force" dominated by white males. It says the government indirectly has done this in a variety of powerful ways, from giving special aid to (mostly white male) veterans to establishing Social Security and welfare systems that discourage women from working. These government programs have been at cross-purposes with federal civil rights laws, Sears argues, preventing private employers from achieving acceptable degrees of racial and sexual desegregation.

The basic federal law forbidding discrimination in employment was passed as part of the Civil Rights Act of 1964. That act also created the EEOC as the government's main enforcement agency -- but then stripped the agency of almost all enforcement powers.

The EEOC was allowed only to receive and attempt to conciliate individual complaints of discrimination. It could neither adjudicate them, nor even take them into court to have them adjudicated. If conciliation failed it could only ask the Justice Department to file suit, or urge the complaining employe to do so privately.

In 1972, after lengthy debate, Congress finally agreed to enlarge the EEOC's powers at least to the extent that, if conciliation failed, it could bring suit on its own.

The next year, then EEOC Chairman William H. Brown III moved to make use of new power by filing complaints against a number of large companies and unions, accusing them of discrimination.

One of Brown's targets was Sears, against which the EEOC had received several hundred complaints that Brown consolidated and made companywide.

EEOC spent almost four years investigating Sears' employment practices and occasionally informally negotiating with the company as to possible changes.

In April 1977, on the basis of this investigation, the commission decided by 2 to 1 that there was reasonable cause to believe Sears had been violating the equal employment title of the 1964 Civil Rights Act.

Under the law, the commission then had to try in a more formal way to negotiate a settlement with Sears before it could go to court. Until it goes to court there are strict legal limits on what the commission can publicly disclose in pending cases.

It is these statutory restrictions on which the Court of Appeals based its suppression decision last year. The commission was moving to give copies of its April 1977, decision to some of the individual Sears employes who had lodged complaints against the company. The court at Sears' request forbade this.

Sears, in its suit last month, said that, "as one of the nation's largest employers," it is "committed to and has expended millions of dollars toward the realization of equal employment opportunity."

But the EEOC, in its 1977 decision, a partial copy of which has been obtained by The Post, found otherwise.

The decision asserted that "nearly 100 percent of major personnel decisions" at Sears "are made by a network of Anglo male supervisors without the benefit of objective standards."

The commission noted that, in 1976, almost 219,000 of Sears' employes, a litted over half, were women. Its investigation "revealed seven major patterns of discrimination" against these women, it said.

It found that:

"Women are significantly underrepresented in the most important managerial and administrative positions in the company." It noted that "9.9 percent of all male employes at Sears are on salary," meaning in the upper echelons, "while only 1.1 percent of all female employes are so classified."

"in retail stores, women hold 77 percent of the lower paying, noncommission sales jobs and only 23 percent of the desirable commission sales positions," and that is "a direct result of Sears' policy" in recruiting and hiring.

Some departments also are sexsegregated, or nearly so, to the disadvantage of female employes. The decision noted, for example, that men dominate the so-called "big-ticket divisions," the furniture and appliance departments.

"Those women who have been promoted, have been denied equal pay for equal work." In departments where women tend to be made managers, the managerial pay rates are lower than in those departments whose managers tend to be men.

"Women hold a disproportionateately high number of the part-time jobs," and "this disparate placement of women in part-time positions adversely affects their opportunities for advancement, their employe benefits and, in many cases, their rate of pay."

The commission also found evidence of discrimination against blacks and those with Spanish surnames. It noted, for example, that "a disproportionately greater percentage of blacks and Spanish-surnamed Americans, both male and female, work in CMDCs (Sears' catalogue centers) them in retail stores" in the same metropolitan areas.

It also noted that, "in more than one-third of the major sales support departments, the work force is underor overrepresented by race or national origin. In general, minorities are assigned to lower-paying, less desirable departments.... These departments include most of the laborer and maintenance jobs found primarily in the CMDCs."

There has been no indication of what relief the EEOC may seek from Sears in the suit it is expected to file sometime in the next several weeks.

In other such cases, the agency has sought back pay for those found to have been discriminated against, plus special treatment in the future in the form of affirmative action.

Sears said in its suit last month that it was accommodating rather than restricting women by offering them so many part-time jobs. It also noted yesterday that it has increased its employment of members of minority groups 250 percent in the last 13 years, that members of such groups now make up 19.9 percent of all Sears employes, and that of all "officials and managers," minority-group members made up 10.5 percent and women 36 percent at the end of 1977.

Sears also says in its suit that it does have objective hiring and promotion standards. It also says the federal statistics used as the basis for EEOC's charge are seriously flawed.