Boston zoning officials on Tuesday approved a proposal for a medical marijuana dispensary on Newbury Street in the Back Bay, overriding neighbors who said the facility was too close to residences and would cause traffic problems.

The unanimous vote by the city’s seven-member Zoning Board of Appeal removes a major hurdle for the dispensary group, Compassionate Organics, which had abandoned an earlier bid to open a facility in Allston amid opposition from that neighborhood’s city councilor.

“I was delighted with the outcome,’’ Compassionate Organics chief executive Geoffrey Reilinger said. “We’re excited to start serving patients in the neighborhood I grew up in.’’

The approval hinges on several conditions: Compassionate Organics can only sell marijuana products to registered medical patients, and cannot enter the recreational pot market without the board’s approval. It must also provide 10 free parking spaces for customers at nearby garages and pay for police details on the Commonwealth Avenue Mall to prevent public consumption of marijuana, which is illegal.

The zoning board said it would officially sign off on its vote once Compassionate Organics provides copies of its contracts with parking garages and a detailed security plan.

Reilinger has pledged that the retail facility at 331 Newbury St., which still needs final approval from state health regulators, will remain medical-only. His group estimated it would attract an average of about 350 patients a day.

The dispensary would be supplied by a 30,000-square-foot marijuana cultivation and processing facility Compassionate Organics has proposed building in Fitchburg.

Larry DiCara, a former Boston city councilor and attorney who represents some of the neighbors opposed to the dispensary, said he may challenge the zoning board’s decision in court.

“The neighbors and property owners are disappointed,’’ said DiCara, who has argued that the dispensary would worsen the neighborhood’s traffic woes, is too close to residences, and may worsen crime in the area.

Numerous residents testified for and against the proposed dispensary; some argued it would bring relief to sick patients, while others said it was a poor fit in one of Boston’s premier retail districts.

A representative of Martin J. Walsh’s office told the zoning board that the mayor respected the City Council’s earlier vote to issue the proposed dispensary a letter of non-opposition, and did not support or oppose the proposal.

The city councilor for the area, Joshua Zakim, had supported the letter of non-opposition. But one of his aides, Kate Bell, testified against the dispensary at the board hearing Tuesday night, saying Zakim had become swayed by the neighbors’ “serious concerns about traffic, deliveries, and the precedent this could set for the neighborhood.’’

Reilinger said he wasn’t concerned by the prospect of a legal challenge, pointing to the concessions Compassionate Organics made in response to neighbors’ concerns and noting that other medical dispensaries have had few problems with their host municipalities.

Dan Adams can be reached at daniel.adams@globe.com. Follow him on Twitter @Dan_Adams86.