For the first time in decades, Harvard is hosting a group of visiting undergraduates from the Soviet Union, University officials said this week.

Four students from Moscow State University have come to Harvard this fall to study math and chemistry as part of the two-year-old U.S.-U.S.S.R. Student Exchange Program.

Selected on the basis of "a combination of grades, activities, character, friend-liness and knowledge of English," Elena F. Putilina, a Soviet chemistry major participating in the exchange program, said she and her comrades will remain at Harvard through the end of this school year.

The program was designed to give Soviet students "a chance to study in their fields and to learn of college life in America" said Jurij Striedter, master of Cabot House, where two of the four Soviet students live.

In the past, Striedter said, the Soviet emphasis on intense study of one subject has been viewed as incompatible with the American emphasis on a broad liberal arts education. This difference, combined with a cool political climate, has limited Soviet access to American undergraduate education, he added.

Describing what she called the differences between the Soviet and American university systems, Putilina said, "here we can choose in the U.S.S.R. we cannot."

But this year's exchange proves that these obstacles are being overcome, said Alex S. Fetisov, leader of the Soviet exchange group.

"We are children of perestroika," Fetisov said, linking the program's success to recent political changes in the Soviet Union.

The Soviet students, accustomed to a free educational system, said the high cost of American colleges is one of the most surprising aspects of life in the U.S.

"I was quite surprised when my lab instructor told us we had to buy liquid nitrogen; in the U.S.S.R. we just take it," Putilina said.

Students said they were impressed with the sense of community that the Harvard housing system provides. "At Harvard there is a natural feeling in the houses," Fetisov said. "Perhaps we will persuade our chiefs to follow suit."

The exchange program is also designed to give Harvard students exposure to another culture and increase dialogue between the two countries, said Thomas A. Dingman '67, assistant dean for the house system.

"It is difficult to think of the U.S.S.R. as a great monolith and to hold rigidly to your views of an adversarial relationship when you get to know individuals," said Dingman, who has been involved in the Harvard exchange since its inception.

Although the number of Soviet students in the U.S. is still relatively low in comparison to some other countries, Fetisov said he is hopeful that the figures will increase.

"It is a friendly way to get to know each other, and I think the numbers will increase quickly," Fetisov said. "They have increased quickly over the past few years."

But one administrator said that the program will only flourish as long as it is seen as a contribution to student life at Harvard.

"It is unlikely that Harvard will continue to make this effort if it does not appear that there is some kind of a positive result," said Alexandra L. Barcus, the senior tutor of Lowell House, where two of the Soviet students live.

Fetisov added that he encourages students to take advantage of the exchange, saying, "Everybody at Harvard should get in touch with the Soviet students to discover what they are like."