BALTIMORE, DEC. 7 -- An employment agency owner pleaded guilty today to violating immigration laws in what prosecutors said was a lucrative nanny-for-hire network that brought hundreds of illegal Trinidadian women into the United States to work in homes in the Washington-Baltimore area.

Samuel Kaplan, 58, owner of Select Employment Services in suburban Baltimore, pleaded guilty in federal court to one count of inducing an illegal alien to enter the United States and a second count of referring another to a job for a fee.

He faces up to 5 1/2 years in prison and $253,000 in fines.

Sentencing was scheduled for Feb. 13 by U.S. District Judge Herbert F. Murray.

Immigration and Naturalization Service officials said Kaplan's plea is the first of its kind under the Immigration Reform Control Act of 1986.

While the plea was limited to two counts, prosecutors said Kaplan engaged in a broad pattern of violations over several years.

In a statement of facts filed in court today, prosecutors Geoffrey R. Garinther and Joseph L. Evans estimated that Kaplan brought in 600 women from Trinidad and other Caribbean islands from 1986 to March 1989, grossing hundreds of thousands of dollars in placement fees from the women. Many paid $2,000 to $2,500 each. Kaplan kicked back part of the fees to three agents in Trinidad, who helped him recruit the women, the proscutors said.

Under Kaplan's instructions, they said, the women entered the United States under the guise of vacationing and had no work permits, or green cards, issued by the immigration service allowing them to hold jobs in the United States.

Kaplan would then place the women with families seeking live-in child-care help in the Washington-Baltimore area.

Garinther and Evans said the women typically were paid $135 to $200 a week, considerably less than their American counterparts. None of them was physically abused, the prosecutors said, and all lived in comfortable, upper-middle-class homes.

Kaplan also helped many in applying for green cards, according to the prosecutors, but since that process takes 2 1/2 to four years, the women's temporary visitor visas expired, making their presence illegal.

Garinther said none of the women had been charged or deported. Under "cooperation agreements" several signed with prosecutors to provide evidence against Kaplan, they will be allowed to return to Trinidad and then apply for readmission to the United States.