Judge Fred B. Ugast, a member of the D.C. Superior Court for 13 years, was selected last night to be chief judge of the court, succeeding H. Carl Moultrie I, who died last month of bone cancer.

Ugast, 62, a former Justice Department attorney who has held a number of the court's most important jobs, will assume his new position Sunday.

The D.C. Judicial Nomination Commission reached its decision yesterday after a four-hour, closed-door session that included interviews with four candidates. According to sources, Ugast was selected on the second ballot.

Chairman Wiley Branton said last night that the seven-member commission had been impressed primarily with Ugast's "prior experience in judicial administration." Ugast, the presiding judge of the criminal division, had been acting chief judge during many of Moultrie's absences and was regarded as Moultrie's right-hand man for much of the past year and a half.

The other Superior Court judges the commission was considering are Gladys Kessler, Ricardo M. Urbina and Paul R. Webber III.

Sources said last night that in a straw vote preceding the two ballots, each candidate received at least one vote. "We concluded all of them were qualified," said Branton. "It was our opinion any one of them would have made a good chief judge."

Ugast said in a telephone interview last night that he was "very honored and very pleased" and that he looked forward to "working with all the judges of the court." Ugast said he planned to look at ways to reduce delays in the chronically overburdened court calendar and to increase the use of hearing commissioners in pretrial matters in an effort to make more judges available for trials. Ugast said that although he had no specific plans, he intended to meet soon with members of the various court divisions and to seek their ideas on court procedures.

"We've got to do it all together," said Ugast, who planned to address the court's judges at a meeting this morning. "I want everybody to feel they are participating in the decision-making process."

Before their meeting with the commission, the four candidates had been asked to address six areas, including discussing their leadership and legal capabilities. Commission members said yesterday they had been impressed with Ugast's responses.

"His statements to the commission exhibited a really good grasp of the court structure and what the problems are over there," Branton said.

Ugast, who lives in Montgomery County, was expected to run into difficulties with the commission be- cause he is not a District resident. Commission members said yesterday that reservations had been raised by some members regarding Ugast's residence, but that the commission "as a whole" recognized Ugast's promise to move into the District if selected.

"The point was made that he was born in the District, reared in the District and lived just over the line of the District," said one member.

Other sources said yesterday that key support for Ugast came from his fellow judges on the bench when they addressed the commission in interviews last week, and in letters.

As the principal administrator of the court, Ugast will supervise the court's 51 judges and oversee a support staff of about 1,000. The Superior Court is the District's main trial court, where the majority of criminal and civil proceedings are adjudicated for District residents.

In addition to acting as presiding judge of the criminal division, Ugast headed the court's important sentencing guidelines commission and headed a number of mental health commissions, one of his primary areas of concern.

During his tenure at Superior Court, Ugast presided over several of the court's most serious and provocative criminal trials, including the case of three men accused of conspiring to assassinate Iranian exile Ali Akbar Tabatabai.

Before joining the bench, Ugast, a Harvard Law School graduate, worked as a lawyer for 20 years with the Justice Department, including a position as deputy assistant attorney general in the tax division. President Nixon appointed Ugast, a Republican, to the bench in 1973.

In addition to Branton, commission members are U.S. District Judge Harold H. Greene (the former chief judge of the D.C. Superior Court), business leader John Hechinger, labor leader William Lucy, former bar president Stephen J. Pollak and lawyers Carl S. Rauh and Linda R. Singer.