Some come as nevozvrashchentsy, or defectors. Others leave with an exit visa in hand, headed for Israel, Europe, or, most often, the United States. Still others marry foreigners for convenience - fiktivny brak - and leave on their new spouse's coattails.
All are Soviet emigres. And many find taking that final step away from their homeland to be a wrenching experience. Why do they do it?
Kirill Shuranov (a pseudonym), an artist who has lived in the United States for 10 months, has difficulty articulating his feelings. Finally, he concludes: ''Before I died, I wanted to understand the world in which I live.''
Artists often choose to escape the constraints of a state-mandated artistic code. For others, relatives living abroad are a strong pull.
Then there are those who simply tire of waiting in lines for a limited choice of food, and leave for the West in search of more consumer goods and a better day-to-day life.
Soviet Jews are by far the largest percentage of those who leave the Soviet Union. For many of them, anti-Semitism at school, at work, and on the street becomes intolerable.
The emigration of Soviet Jews, which burgeoned in the 1970s, has slowed to a trickle in the early '80s. At its height, the USSR allowed anywhere from 13,000 to more than 51,000 Jews to leave yearly. But, according to a spokesman for Action for Soviet Jewry in Waltham, Mass., only 2,207 were permitted to leave in the first nine months of this year.
Volodya Kaplan (not his real name), a successful civil engineer in Moscow, left the Soviet Union 3 1/2 years ago at the age of 43. He and his wife applied to leave after receiving invitations from ''family'' to join them in Tel Aviv. Mr. Kaplan soon lost his job and supported himself by selling his car and furniture. During the 13-month wait for the visa, the constant threat of jail hung over his head. His would-be crime: unemployment.
The Kaplans came out with $113 each, leaving most of their belongings behind as the Soviet government requires. After three months in Rome, they came to New York City, where they were resettled by the New York Association for New Americans (NYANA), the largest Jewish resettlement agency in the country. The association helped the Kaplans with various aspects of American life - from basic English training to job counseling to Jewish cultural education - while also providing financial support.
The Kaplans had left behind what appeared to be a comfortable middle-class life. ''I was promoted quickly, had a good career, and plenty of respect,'' Volodya, a soft-spoken man, recalls. ''But sometimes my boss would say to me, 'Sit at the back of this meeting, the bosses from the party committee don't like Jewish faces.' At the same time, though, he would send me out on the toughest jobs.''
He had faced similar difficulties in his schooling. Although he attended a good institute, he was accepted only after receiving excellent scores in a correspondence course. Such reminders of his Jewish ''nationality,'' he says, ''created an unpleasant pressure which wasn't terrible . . . but (yet) it was.''
Although his first job in the US was driving a taxi, Mr. Kaplan never regretted leaving the USSR. Pulling up roots and leaving friends was painful, but, he asserts quietly, ''I knew it was a right step, a necessary step.''
After 18 months of shepherding New Yorkers around and sending out resumes in his spare time (''50 or 60 every Monday''), he found work as a contractor. ''I knew I'd get what I worked for,'' Kaplan recalls with a smile. ''Nobody will help you, but nobody will stop you. You have two hands, you can go ahead.''
The transition for some is more difficult than it was for the Kaplans, who are now able to reimburse NYANA for its aid. Many immigrants, especially those well into middle and old age, have a hard time learning English and simply give up trying. Welfare, disability, and supplemental security income become the major sources of income for some older immigrants lacking close family to support them.
Any NYANA social worker can recount many of the unique problems and demands their clients face.
One elderly woman wrote a pleading letter to the association about her son, who was spending all her food money on his girlfriend. She claimed there were no table and chairs in her apartment, just an old mattress her son had found on the street.
In another instance, a three-generation family staged an eight-hour sit-in in their social worker's office, insisting that the association rent three separate apartments for them. They sat in vain.
Having grown up in a welfare state, many Soviet immigrants expect similar treatment from the American system. They become indignant when NYANA tells them that after about six months, they will be on their own financially. Discovering that American streets are not ''paved with gold'' can heighten this disillusionment.
Yet despite the difficulties of resettlement, ''80 percent of NYANA clientele become employed within their first year here,'' points out Edna Rosenman, the association's director of social services.
Many Russian immigrants leave not as young people eager to buck the Soviet system and move to a freer country, but as middle-aged people who have become worn down by some aspect of their life in the Soviet Union. Felix Zbarsky, a sculptor living in New York's Greenwich Village, suggests that at a certain point, ''enough is enough. The artists are not young who leave. They realize at a certain point there's nothing more to achieve.
''When you are young and you have the energy to fight, it's OK. But when you achieve something, that's the worst. Then they limit you. You can't do what you want.''
Mr. Zbarsky mentions his friend Yevgeny Yevtushenko, the well-known contemporary Soviet poet, whose work, in Mr. Zbarsky's eyes, achieved great stature but then declined as he succumbed to government pressure to be noncontroversial.
''So you leave,'' the middle-aged sculptor says matter-of-factly.
A tall, irrepressible man, he speaks fluently and ebulliently about the similarities the city shares with his former home, Moscow. Mr. Zbarsky seems completely relaxed in his full-floor loft, surrounded by his sculpture.
''New York is the center,'' he remarks enthusiastically. ''In Moscow, I had trouble getting things accepted for group exhibitions. I had many successes, too , but my work does not go in the stream of 'socialist realism,' '' he adds, smiling wryly.
Kirill Shuranov, who was a book illustrator in Moscow and a member of the Artists' Union, shares some of Felix Zbarsky's sentiments about leaving. ''Maybe I would have left earlier,'' he reflects as he sits in the comfortable Connecticut home he shares with friends. His green eyes appear thoughtful, even a bit mournful. ''But it is hard to leave. It was like dying and being born again. At night I have dreams about Russia, but I have no regrets about leaving.''
Mr. Shuranov points out that he was fortunate enough to have friends here to help him settle when he left the Soviet Union. Given his limited English, he associates mostly with Russians, though he feels the US gives him the freedom to blend in that few other countries could offer.
''There isn't much snobbism here,'' he explains. ''Anyone can belong.''