18-30 years of age for compulsory military service;
2-year conscript service obligation (2007)

Uganda
18-26 years of age for compulsory and voluntary military
duty; 18-30 years of age for professionals; 9-year service
obligation; the government has stated that recruitment below 18
years of age could occur with proper consent and that "no person
under the apparent age of 13 years shall be enrolled in the armed
forces"; Ugandan citizenship and secondary education required (2008)

Ukraine
18-25 years of age for compulsory and voluntary military
service; conscript service obligation - 18 months for Army and Air
Force, 24 months for Navy (2004)

United Arab Emirates
18 years of age (est.) for voluntary military
service; 18 years of age for officers and women; no conscription
(2008)

United Kingdom
16-33 years of age (officers 17-28) for voluntary
military service (with parental consent under 18); women serve in
military services, but are excluded from ground combat positions and
some naval postings; must be citizen of the UK, Commonwealth, or
Republic of Ireland; reservists serve a minimum of 3 years, to age
45 or 55; 16 years of age for voluntary military service by Nepalese
citizens in the Brigade of the Gurkhas; 16-34 years of age for
voluntary military service by Papua New Guinean citizens (2008)

United States
18 years of age (17 years of age with parental
consent) for male and female voluntary service; maximum enlistment
age 42 (Army), 27 (Air Force), 34 (Navy), 28 (Marines); service
obligation 8 years, including 2-5 years active duty (Army), 2 years
active (Navy), 4 years active (Air Force, Marines) (2008)

Uruguay
18 years of age for voluntary and compulsory military
service; enlistment is voluntary in peacetime, but the government
has the authority to conscript in emergencies (2007)

Uzbekistan
18 years of age for compulsory military service; 1-year
conscript service obligation; moving toward a professional military,
but conscription will continue; the military cannot accommodate
everyone who wishes to enlist, and competition for entrance into the
military is similar to the competition for admission to universities
(2007)

Venezuela
18-30 years of age for compulsory and voluntary military
service; 30-month conscript service obligation - all citizens 18-50
years old are obligated to register for military service (2008)