A federal judge in Baltimore said yesterday that an apartment management company owned by Bethesda developer and Maryland Democratic Party Chairman Nathan Landow has failed to comply with a 1987 agreement that resolved a housing discrimination lawsuit.

U.S. District Judge Marvin J. Garbis ordered the company to meet all the terms of the original agreement for the next two years.

In the 1987 settlement, Landow's company paid $20,000 to the Fair Housing Council of Greater Washington and said it would not discriminate against applicants for apartments because of race. The company also agreed to educate employees about fair housing law, display fair housing posters and lists of available units in their buildings, include equal opportunity slogans in advertising and give all applicants written descriptions of rental and waiting list policies.

The Fair Housing Council is a group of human rights and religious organizations that periodically conducts widespread testing of Washington area rental housing. In 1986 a black tester went to the Landow apartment building at 4710 Bethesda Ave. and was told by a rental agent that a one-bedroom apartment would be available two months later but that "we have cockroaches everywhere," according to the lawsuit. Earlier the same day, the agent had told a white tester that two one-bedroom apartments would be available soon and that the building had no roaches, the suit said.

The council filed a second suit against the Landow company in February 1988, saying the firm had not complied with the 1987 agreement and that it had violated fair housing laws.

Judge Garbis said yesterday the Landow company did not comply with terms of the settlement agreement but that the firm did not violate the anti-discrimination laws.

"We're pleased that the judge found Nathan Landow had not lived up to his duties and obligations to the Fair Housing Council and pleased that he put them under a fair housing order, but we think the judge was mistaken about the fair housing act claim," said John Relman, of the Washington Lawyers Committee for Civil Rights Under Law. The lawyers committee represented the Fair Housing Council in the case.

The Landow company's failure to comply was due to "neglect and inadvertence" and occurred only during the first year of the agreement, said David R. Boyd, who represented the firm. The company's "position is that for the second year, once the neglect was called to our attention, we got into compliance."