Some previous studies have suggested that coffee stiffens arteries, with drinkers warned to cut down their consumption of the caffeine-laden drink.
But a survey of more than 8,000 people across the UK found that drinking five cups a day, and even up to 25, was no worse for the arteries than drinking less than a cup a day.
The research, part-funded by the British Heart Foundation (BHF), is being presented at the British Cardiovascular Society Conference in Manchester.
Experts from Queen Mary University of London divided 8,412 people into three groups for the study.
The first group was of those who drink less than one cup of coffee a day, the second was of those who drink between one and three cups a day and the third was those who drink more than three.
Some people in the last group drank up to 25 cups a day, although the average for this group was five cups a day.
Doctors found that even those drinking up to 25 cups of coffee a day were no more likely to have stiffening of arteries than those who drank less than one cup a day.
Previous studies have suggested that coffee stiffens arteries, putting pressure on the heart and increasing the likelihood of a heart attack or stroke.
All the participants in the latest study underwent MRI heart scans and infrared pulse wave tests, and the results held true even after factors such as age, weight and smoking status were taken into account.
Dr Kenneth Fung, from Queen Mary University of London, said: “Despite the huge popularity of coffee worldwide, different reports could put people off from enjoying it.
“While we can’t prove a causal link in this study, our research indicates coffee isn’t as bad for the arteries as previous studies would suggest.
“Although our study included individuals who drink up to 25 cups a day, the average intake among the highest coffee consumption group was five cups a day.
“We would like to study these people more closely in our future work so that we can help to advise safe limits.”
A second study led by Aston University and presented at the same conference found that people admitted to several NHS hospitals with a cardiac arrest over the weekend did not face a higher risk of dying compared with those admitted during the week.