Doctors seeking Upper East Side office space soon will have the option of buying into a “medical condominium” that is being designed exclusively for their use.

Construction has recently begun on the building, at 429 E. 75th St., which will feature six stories of medical office space inside a structure formerly used as a garage.

The developers said they envision the completed building as a “mini medical community” where doctors’ services will complement each other.

“If you look at the Upper East Side, with NewYork-Presbyterian and Sloan-Kettering, we feel we’re delivering large blocks of contiguous space to really benefit today’s modern practices,” the managing partner of ABR Partners, Brian Ray, said. In addition to ABR Partners, Taconic Investment Partners worked to develop the site.

Those familiar with the city’s market for medical office space said the flurry of recent residential development has created a shortage of medical space.

“Doctors are having a tougher and tougher time finding space,” a Corcoran broker who is the leasing agent for the East 75th Street condominium, Paul Wexler, said.

Plans for the medical condominium call for the existing structure to receive three new floors, new elevators, an upgraded telecommunications system, and a cooling tower. Once completed, the building will have 35,000 square feet of office space, or roughly one medical practice a floor.

Space in the building, set to be completed in January 2008, costs about $1,100 a square foot, and each unit will be designed according to the doctor’s specifications. So far, no physicians have finalized contracts for space, although several have expressed interest, Mr. Wexler said.

The concept for an all-medical condominium is a departure from traditional models for medical offices in the city, where just a handful of buildings cater exclusively to doctors. For the most part, those building are owned by hospitals or have gradually accumulated a high proportion of medical tenants.

“What has existed for a good number of years in the suburbs has not been as easily created in Manhattan, and typically doctors are located in these groundfloor units,” Mr. Wexler said, citing city zoning laws that dictate where doctors’ offices may be located. The condominium project was able to move forward because the space previously was employed as a garage, a nonconforming use for the neighborhood, he said.

Developers not associated with the East 75th Street project described the market for medical office space as one with reliable consumers. “Medical space is big business,” the vice president of M&R Management Company, Jeffrey Kerr, said.

More than a decade ago, Mr. Kerr’s company, which owns rental apartment buildings in Brooklyn and Manhattan, recognized that it was more profitable to rent lobby apartments to doctors, who typically have good credit and stay for the duration of their career. About three years ago, the company decided to construct an independent medical office building, and it recently completed such a rental facility in the Midwood section of Brooklyn.

However, doctors may consider the condominium model an attractive business opportunity. Condominiums tend to be less restrictive than co-ops, where boards often require doctors to pay significant sums of money up front.

“It’s hard for a doctor, particularly a young doctor, to come up with a million bucks,” a broker with Prudential Douglas Elliman, Jeffrey Tanenbaum, said. According to Dr. Tanenbaum, who worked as a surgeon before his career in real estate, owning a condominium carries the benefit of stability and “a little nest egg.”

Still, Mr. Kerr expressed doubt that the medical condominium concept was the beginning of a new trend rather than an “oddball occurrence.”

“There’s such a large cost associated with building new construction that it’s tough to warrant it,” he said.