The sale of the north section of the Lee Gardens apartments to a nonprofit Arlington housing group was made final yesterday, ensuring that 200 of the units at the complex will go to low-income tenants.

The sale's completion marks the end of a year-long effort by community groups and county officials to help some of the 3,000 mostly poor Hispanic tenants who are being displaced by the renovation of the complex off Rte. 50.

The 364 units in north Lee Gardens was purchased by the Arlington Housing Corp. from the Artery Organization of Bethesda. Though the county does not own the units, the sale agreement was brokered at every step by Arlington officials.

The agreement also involves the state-chartered Virginia Housing Development Authority, which is providing $33.6 million in bond financing toward the purchase and rehabilitation of the northern section. Federal rent subsidies will allow 200 of the units to go to low-income tenants.

Initial sale documents were signed in October, but final settlement hinged on the resolution of Artery's negotiations with its lenders.

At a brief ceremony in front of one of the dilapidated brick garden apartment buildings at the complex, Arthur R. Lieverman, a member of the board of the housing corporation, signed the purchase agreement.

"There are many, many people who have worked over a year for this day," he said. "All of us in Arlington should be grateful."

Daniel R. Mackesey, an Artery vice president, presented a check for $1.076 million, a donation toward the price of $18.2 million. Mackesey said the firm could have simply reduced the price but wanted to underscore its contribution.

Artery bought the 961-unit Lee Gardens apartments last year. But its plans for an expensive rehabilitation raised concern among county officials that the tenants would be displaced.

Artery is still renovating the south part of the complex, which has been renamed Sheffield Court. Mackesey said fewer than 100 of the units on the south side are still occupied. Tenants in those units can stay until the end of January.

Lou Ann Frederick, executive director of the Arlington Housing Corp., said renovations of the north section will be completed by the summer of 1989.