The 2,440 students appearing for the national pharmacy licensing test were caught cheating in the Chinese city of Xi'an in Shaanxi province.
The cheating candidates wore ear-phones through which answers to the test questions were transmitted via radio.
The scam earlier this month was uncovered when invigilators detected abnormal radio signals from an illegal frequency.
"It is the worst scandal over the past few years," Du Fangshuai, the chief of Shaanxi testing authority, was quoted as saying by the Hong Kong-based paper South China Morning Post.
The total number of students caught cheating accounted for almost one in 10 of the 25,000 candidates who appeared for the test in the province.
One of the pharmacists caught cheating said half of the test takers at one exam centre were wearing the same ear-piece.
"I don't know why but some were not caught," he was quoted as saying by the paper.
Local police have arrested several people, who were allegedly behind the scam and are continuing to investigate.
"Candidates found cheating would be banned from taking any national licensing test for two years," Du said.
Pharmacists are in great demand in Shaanxi amid a shortage of qualified staff. Shaanxi has just 4,000 licensed pharmacists - not enough to staff 8,500 pharmacies and medicine wholesale firms across the province.
But the licensing test, consisting of seven separate two-and-a-half hour exams, remains highly competitive.
