Viral warts are extremely common and their treatment can represent a significant part of a Dermatologist's workload. Cryotherapy is probably the treatment most frequently adopted by the Dermatologist. The response rates can vary considerably for a number of reasons. Careful attention to cryotherapy technique is important to obtain optimal response rates and minimize the hazards.The most frequently used coolant is liquid nitrogen and this is the only coolant on which any significant research has been performed. This treatment is potentially hazardous and cryotherapy should never be undertaken by doctors or nurses without adequate training. The aim of the treatment is to induce inflammation and an immune response, not complete necrosis of the skin containing the wart. Overtreatment runs risks of scarring and damage to nerves, blood vessels, nail matrix, joints and tendons.The use of liquid nitrogen cryosprays (or guns ) is convenient and popular although these are expensive and offer no established advantage, in terms of efficacy or tolerability, over the traditional bud of cotton wool. Paring away callosity prior to freezing significantly improves the response of plantar warts. Warts should be frozen until ice has spread from the centre of the lesion to form a continuous halo around the edge and the freeze is usually maintained for 5 seconds. For plantar warts, the use of a second freeze-thaw cycle improves the response. Treatment is probably best repeated at intervals of 2 weeks. The use of keratolytic wart paints by the patients in between appointments seems helpful.