Mums and dads worry they have no control over sexts, cyber bullying and other threats.
Recent studies have shown children are likely to receive their first mobile phone at around 12-years-old, while a growing number of adults pacify those even younger with limited time on their own devices when completing errands.
Research from security provider AdaptiveMobile shows 55 per cent of UK parents think mobiles are the hardest devices to monitor, when compared to the likes of games consoles and laptops.
65 per cent worry that their kids are at risk from cyber bullying, sexting and unrestricted access to inappropriate content.
51 per cent admit they would like more control over their child's device, and a further 51 per cent would like to see who they're kids are talking to, while 52 per cent would like to know what they're looking at.
Gareth Maclachlan, COO and co-founder, AdaptiveMobile, said: "Concern over these threats and specifically child safety and wellbeing is actually causing a quarter of parents not to give their children mobile phones; a real shame when you consider what a great tool for advancement and development they can be."
Meanwhile, 69 per cent of the folks have discussed cyber bullying with their offspring, and 32 per cent have talked about sexting risks.
89 per cent consider it to be their duty to protect their children against smartphones, but 26 per cent think the operator should be held accountable.