A Fairfax County Circuit Court jury awarded $175,000 yesterday to the parents of a baby who died of a drug overdose three years ago while in the care of her babysitter, Martha E. Guba.

The award came after a three-day trial in an unusual case of negligent entrustment that pitted the parents, Ronald and Jane Snead, against Guba's daughter and son-in-law, Gail and Thomas Stephen, who rented the Springfield house to Guba where she ran an infant-care business.

The jury found Gail Stephen, who admitted that she knew her mother had a criminal past and a drug addiction, to be negligent. But jurors did not hold Thomas Stephen liable.

An attorney for Ronald and Jane Snead argued that the Stephens should never have allowed Guba to run an infant-care business out of the house because they knew she had had problems with prescription drugs and had been convicted in 1968 of neglecting her two infant children.

"They knew of her criminal past. They knew she had a drug problem," the Sneads' attorney, Edward L. Weiner, told jurors.

Martha Guba was convicted on Nov. 27, 1989, of felony neglect in the fatal drug poisoning of 10-month-old Ashley Snead. Ashley died in Guba's care on July 28, 1987, from an overdose of the prescription drug imipramine. Guba is serving a 10-year sentence in state prison.

Thomas J. Morris Sr., the Stephens' attorney, told the jury that the Stephens were living in Kansas City, Kan., at the time of the death and did not know of Guba's problem.

"Martha Guba is a con artist. Martha Guba is a conniver. Martha Guba is a drug addict," said Morris, who represented Guba during her criminal trial.

He said Guba told doctors several lies to get drugs, including stories that her husband had died. Each time, Morris said, the doctors prescribed medication. He said that if Guba could have misled doctors, she could have fooled her daughter.

Prosecutors argued during the criminal case that Guba gave Ashley the drug over an unknown number of days to keep the child quiet. Guba's attorney maintained that the baby found the drug in a trash can.

Since Ashley's death, the Sneads have launched a national campaign for child-care regulation. Weiner said yesterday that they decided to file suit to bring attention to the problem.