The study has been led by Dr David Veale from King's College London who surveyed around 173 men and asked them to fill out a questionnaire that questioned them about their body image, erectile function and penis anxiety.
Around 46 of the recruited men also agreed to have their penis size measured up, both when flaccid and erect.
The researchers found that around 30 percent of the men were unhappy with their penis size while 35 were content, with the remaining falling between being happy and unhappy. Older men and homosexual men were the most anxious about their penis size. The size of the penis of those measured ranged from seven to 10cms long and seven to 13cms in terms of girth when flaccid but stretched and 10 to 20cms long and nine to 17cms in girth when erect.