Researchers said that they decided to tackle the topic as past studies had offered conflicting answers, and may have been sullied by asking the women too directly.
Lead author Brian Mautz, a postdoctoral researcher in evolution and sexual selection at the University of Ottawa, used computer-generated images of generic male figures with varying heights, body shapes and flaccid penis lengths.
A sample of 105 Australian women were then asked to look at 53 of these life-sized robot-like pictures, which rotated so that they were visible at different angles.
The women - all heterosexual - were not told that they were taking part in a study about penis size and were simply asked to rate the figures according to sexual attractiveness.
Researchers found that the women rated tall men with long penises as the most attractive and they also tended to gaze longer at the larger men, Health24 reported.
The study has been published in Proceedings of the National Academy of Sciences (PNAS).