Mary Treadwell, the former director of Youth Pride, Inc., told a federal judge yesterday that she has outstanding debts totaling $66,512 and therefore cannot hire a lawyer to adequately defend her against fraud charges.

In a financial statement submitted to U.S. District Judge John Garrett Penn, Treadwell said she has $23,250 in assets, but that $16,000 of that amount is tied up in a loan she made to the buyers of a house she owned on Capitol Hill. The loan is not due until December 1983.

Treadwell, who said her total monthly income is $784 in unemployment insurance, sold her house at 411 Seventh St. NE for $115,000 last December.

She said yesterday that $5,000 of the cash proceeds from the sale went to her former husband, Mayor Marion Barry, under the terms of their 1977 divorce. The mayor's office confirmed that the amount represented $3,500 in equity in the property and $1,500 in interest.

According to the financial statement, Treadwell's assets include $1,200 in cash, $250 in bank accounts, and $5,800 in personal property, including clothing, jewelry, furniture and art.

Liabilities include about $53,655 in unpaid federal income taxes from 1976 through 1981, $4,800 in personal loans and $4,774 in credit card bills, the statement said.

Treadwell estimated her average monthly expenses at $1,417 and said her taxable income in 1981 was $21,500. Treadwell said she applied for unemployment shortly after Youth Pride shut down in August.

Treadwell said yesterday that she received $19,000 in cash from the sale of her house, which was used to pay outstanding bills. Treadwell filed the financial statement yesterday in an effort to convince Penn to overturn a federal magistrate's finding that Treadwell did not qualify for a court-appointed lawyer.

Treadwell and four others were indicted last month on charges that they stole and misappropriated thousands of dollars from P.I. Properties, Inc., a real estate spinoff of Youth Pride.

The grand jury charged that Treadwell and the others used P.I. Properties, which they said was a nonprofit organization, to fund other profit-making enterprises and to pay personal expenses.

At a hearing before Penn last week, Treadwell pleaded innocent to the charges against her and asked that a team of lawyers, paid by the court, be appointed to defend her.

Treadwell maintained yesterday that she cannot afford to hire the type of sophisticated legal help she believes she needs to counter the government's complex case against her, which was developed during a 2 1/2-year investigation. A hearing is set for March 22.

Treadwell said in an interview yesterday that she has spent $10,000 on lawyers since late 1979 when the government opened its investigation into Youth Pride and P.I. Properties. Some of that money came from the sale of her car and from the sale of her house, Treadwell said.