About one-fifth of the female motorists surveyed confessed that they had touched up their mascara on the move - equivalent to 2.7 million of Britain's 15 million women drivers.
Three per cent admitted causing a collision when distracted by applying cosmetics.
The poll of 4,000 women drivers by women's motor insurer Diamond comes a year after the introduction of a new offence of causing death by careless driving, which carries a prison sentence of up to two years.
Earlier, careless driving offences - including applying make-up, eating and map reading - were punishable only by a fine.
The survey found that young women, aged between 17 and 21, were most likely to put beauty before safety and most liable to crash their car as a result.
Twenty-seven per cent women confessed to putting on make-up and nine per cent of those aged 18 or younger have had a crash while doing so, which is three times the average.
However, only six per cent of women aged 56 or older are least likely to do it at the wheel and just one in 200 - 0.5 per cent - in that age group have had an accident while applying make-up.
Diamond managing director Sian Lewis said it is "worrying" that so many women put themselves and other road users at risk.
"We all have busy lives but applying your make-up when you're driving means your full attention is not on the road ahead," the Telegraph quoted her as saying.
"Is your mascara more important than yours and other road users' safety? Even if you're lucky enough to arrive at your destination safely, you could be charged with careless driving if spotted by the police.
"Women are generally great at doing more than one thing at once but this is definitely one area where multitasking should not be practised," she added.