The 2003 CIA World Factbook

by United States. Central Intelligence Agency

Uganda
18 years of age; universal

Ukraine
18 years of age; universal

United Arab Emirates
none

United Kingdom
18 years of age; universal

United States
18 years of age; universal

Uruguay
18 years of age; universal and compulsory

Uzbekistan
18 years of age; universal

Vanuatu
18 years of age; universal

Venezuela
18 years of age; universal

Vietnam
18 years of age; universal