The results are from a survey of 1,954 UK diabetics commissioned by Diabetes UK and sponsored by Bristol-Myers Squibb and AstraZeneca.
Overall, 49 per cent of patients experienced a hypo in the past two weeks, and 52 per cent said mild-to-moderate hypos affect their quality of life.
One in 10 patients reported having to take at least one day off work in the past year because of a hypo.
Elsewhere, University of Dundee researchers found that type-2 diabetics with two variants of the gene CYP2C9 respond better to treatment with sulphonyl-ureas, and are 3.4 times more likely to achieve their blood glucose target of less than 7 per cent than patients without the variants.
Dr Iain Frame, director of research at Diabetes UK, said: 'This study adds to the pharmacogenetic field of research which may in time lead to better tailored prescriptions for people with type-2 diabetes.'