Vaccination against infectious diseases came second and imaging developments such as CT and MRI scanning third in the top 20, according to the survey organised by the Royal College of Physicians of Edinburgh (RCPE).
Anti-TB therapy, anti-viral therapy for HIV, statins and kidney dialysis were also in the top 20, as were kidney and liver transplantation and beta- blockers.
The poll was conducted to mark a forthcoming RCPE conference celebrating five decades of medical achievement. It surveyed members throughout the UK and internation- ally.
Dr Neil Dewhurst, president of the RCPE, said advances in medicine in the past 50 years now provided patients with "unprecedented" levels of treatment.
He said: "As an individual, it is difficult to say which singular development has been the most important, as all doctors will have their own views regarding which development has been the most beneficial.
"From this survey it is clear that doctors throughout Scotland, the UK and internationally believe the most important developments to be in relation to the availability of effective antibiotics and vaccination."