Ronald Ellis, who pleaded guilty to killing six persons including his wife and two daughters, was sentenced yesterday in Prince George's County Circuit Court to five consecutive life terms.

The sentence, imposed by Judge Jacob Levin as Ellis stood rigidly before the bench staring blankly ahead, presumably will ensure that the 34-year-old Ellis never is freed. The soonest he could become eligible for parole is in 60 years.

Levin told Ellis that the prosecution had shown "more compassion" than he deserved. In exchange for Ellis's guilty pleas, State's Attorney Arthur A. Marshall Jr. dropped his request for the death penalty in the fatal shootings that took place last May 2 in Ellis's Camp Springs home.

In arguing for leniency, defense attorney R. Kenneth Mundy said "for perhaps 10 to 15 minutes of the 34 years of his life, the real Ron Ellis stepped out of character." Mundy described his client as a "loving father and devoted husband" and not the "bestial brute Mr. Marshall depicts and wants to shut away for the rest of his life."

Relatives and friends said after the slayings, that Ellis and his wife Ingrid, a D.C. police officer, were having serious marital problems and she was leaving and taking the children.

During yesterday's brief hearing, psychiatrist Neil Blumberg testified that three staff doctors at Clifton T. Perkins State Hospital examined Ellis this week and found him legally competent to understand the proceedings against him. However, under questioning by Mundy, Blumberg said that Ellis told doctors that "he was not sure what he was going to plead at this time." When Ellis was questioned during the examination about the fact that he already had pleaded guilty on Monday, he was evasive, Blumberg testified.

In court Monday, when asked by the judge if he had shot each of the six victims, Ellis answered affirmatively. Then the judge asked him in the required legal language, "Are you pleading guilty . . . because you are in fact guilty?" Ellis replied, "As I told you before, your honor, I don't know if I shot anybody."

Nevertheless, Judge Levin found that Ellis had voluntarily changed his plea to guilty, and yesterday, after hearing Blumberg's testimony, the judge asserted, "Based on my participation in this case from its inception. . . I am convinced beyond a reasonable doubt that Mr. Ellis is competent . . . "

Ellis had pleaded guilty to murder in the shotgun shootings of two of his daughters, 12-year-old Tammy and 4-year-old Monica, and of three of his wife's friends -- Janet Jackson, her son Tyrone and Sherry Robinson. In the handgun slaying of his wife, Ellis pleaded to voluntary manslaughter, a lesser charge that does not carry the element of an intentional, purposeful killing. On that charge, Levin sentenced him to 10 years in prison to run concurrently with the life terms.

Under the sentence, Ellis would first be eligible for parole in 75 years. If he earns all the possible time off for good behavior, he could become eligible in 60 years, when he would be 94 years old.

Ellis's father, John D. Ellis Jr., said the family was somewhat relieved that the court ordeal was over. "We'll continue to stand by him. Whatever we can do, we will," the elder Ellis said.

He added that he had never asked his son precisely what happened in the Ellis household last May 2. "It might be that we didn't want to know. It has hurt the family so much, that I'm sure we feel that way."

One of Ellis's three daughters, Tracey, 14, survives. She was not at home at the time of the killings.