Eric M. Breindel, a former staff member of the Senate Select Committee on Intelligence, pleaded guilty yesterday to a misdemeanor charge of possession of heroin stemming from his purchase of five packets of the drug from an undercover police officer May 16.

Assistant U.S. Attorney Roger M. Adelman told the court that Breindel and Winston B. Prude, a former Justice Department lawyer, met the officer in a New York Avenue motel room after Prude was informed by telephone that the heroin was available.

The prosecutor said Breindel paid $150 for the five packets, keeping two of them, while Prude took the other three. The two men were apprehended as they left the Holiday Inn in Northeast Washington where the meeting took place.

"Did you do that?" U.S. District Court Magistrate Jean E. Dwyer asked the 27-year-old Harvard Law School graduate.

"Yes, your honor," Breindel replied in a hoarse voice.

In a written agreement he made with the prosecutor's office, Breindel said he would answer questions about the events leading up to his arrest. In return, the government will inform the court of the extent of Breindel's cooperation when he is sentenced July 15. He is free on bond until then.

Breindel could be sentenced to prison for up to a year or be fined up to $5,000, or both.

The FBI, the Drug Enforcement Administration and District police plan to question Breindel, sources said. Among other matters, they want to make sure no classified data was compromised while he worked for the intelligence committee. Breindel's attorney, William W. Taylor III, has stated that his client did not compromise any information.

In addition, the investigators plan to ask Breindel about others who might have supplied him with drugs, according to sources. The day after his arrest, Sen. Daniel Patrick Moynihan (D-N.Y.), vice chairman of the intelligence committee, asked for and received Breindel's resignation.

As part of the agreement with the government, Breindel signed a statement that outlined the extent of his experience with drugs. The document, which was not made public, states that he started using heroin occasionally in college more than six years ago, according to sources close to the case. At least in part, the sources said, Breindel attributed his use of the drug to a growing dependence on prescription painkillers.

Breindel took the painkillers because of the effects of a kidney operation and a wrestling injury to his wrist, the sources quoted the document as saying.

Breindel's statement does not name any friends as being involved with heroin, the sources said. Under the terms of the agreement, no charges will be brought against Breindel if he admits to other offenses during the debriefing, so long as any such offenses were cited in the proffer.

Prude has not yet entered a plea in his case. He attempted suicide by taking an overdose of the tranquilizer Valium Monday but is out of danger.