The Medical School has obtained its first-choice site for the construction of a new $5 million library, a spokesman for the Administration said last night. The library will be built on the Huntington Ave. land now occupied by the Martin Public School, which has been condemned by the city as unsafe.

Although the University made a $100,000 offer for the land several months ago, Boston's Mayor Hynes did not approve the sale until Friday.

Last spring, the Medical School was considering using the land on Shattuck St., between the School of Public Health and the Administration building. But this location was "always an alternative," the Administration spokesman said, "and one which hopefully would be discarded when we were able to find something better."

The School has needed a new library for many years, but lacked the money to make any definite plans until last February. At that time, Miss Sandra Courtway of Brookline donated $3.5 million to be used for medical research.

"During the past five years, we have raised an additional $1.5 million from other sources," the spokesman added, all of which will be used for the library.

Since the Administration is still negotiating for an architect, no construction date has been set, but one source estimated that work would begin by the end of the academic year.

The new structure will have at least three times the capacity of the present library, and will be architecturally similar to Lamont.