Gadmen had a population (as of 2011) of 228.
 As of 2011, 3.1% of the population are resident foreign nationals.
 Over the last year (2010-2011) the population has changed at a rate of -1.7%.
 Migration accounted for 1.7%, while births and deaths accounted for -3.0%.

Most of the population (as of 2000) speaks German (268 or 98.5%) as their first language, while one person each speaks French and Spanish.

As of 2008, the population was 53.4% male and 46.6% female.
 The population was made up of 123 Swiss men (53.0% of the population) and 1 (0.4%) non-Swiss men.
 There were 102 Swiss women (44.0%) and 6 (2.6%) non-Swiss women.
 Of the population in the municipality, 162 or about 59.6% were born in Gadmen and lived there in 2000.
 There were 42 or 15.4% who were born in the same canton, while 32 or 11.8% were born somewhere else in Switzerland, and 28 or 10.3% were born outside of Switzerland.

As of 2011, children and teenagers (0–19 years old) make up 14.5% of the population, while adults (20–64 years old) make up 61% and seniors (over 64 years old) make up 24.6%.

As of 2000, there were 102 people who were single and never married in the municipality.
 There were 144 married individuals, 22 widows or widowers and 4 individuals who are divorced.

As of 2010, there were 43 households that consist of only one person and 7 households with five or more people.
 In 2000, a total of 100 apartments (67.1% of the total) were permanently occupied, while 35 apartments (23.5%) were seasonally occupied and 14 apartments (9.4%) were empty.
 As of 2010, the construction rate of new housing units was 4.3 new units per 1000 residents.
 The vacancy rate for the municipality, in 2010, was 3.39%.
 In 2011, single family homes made up 70.8% of the total housing in the municipality.

The historical population is given in the following chart:
Gadmen had a population (as of 2011) of 228.  As of 2011, 3.1% of the population are resident foreign nationals.  Over the last year (2010-2011) the population has changed at a rate of -1.7%.  Migration accounted for 1.7%, while births and deaths accounted for -3.0%.
Most of the population (as of 2000) speaks German (268 or 98.5%) as their first language, while one person each speaks French and Spanish.
As of 2008, the population was 53.4% male and 46.6% female.  The population was made up of 123 Swiss men (53.0% of the population) and 1 (0.4%) non-Swiss men.  There were 102 Swiss women (44.0%) and 6 (2.6%) non-Swiss women.  Of the population in the municipality, 162 or about 59.6% were born in Gadmen and lived there in 2000.  There were 42 or 15.4% who were born in the same canton, while 32 or 11.8% were born somewhere else in Switzerland, and 28 or 10.3% were born outside of Switzerland.
As of 2011, children and teenagers (0–19 years old) make up 14.5% of the population, while adults (20–64 years old) make up 61% and seniors (over 64 years old) make up 24.6%.
As of 2000, there were 102 people who were single and never married in the municipality.  There were 144 married individuals, 22 widows or widowers and 4 individuals who are divorced.
As of 2010, there were 43 households that consist of only one person and 7 households with five or more people.  In 2000, a total of 100 apartments (67.1% of the total) were permanently occupied, while 35 apartments (23.5%) were seasonally occupied and 14 apartments (9.4%) were empty.  As of 2010, the construction rate of new housing units was 4.3 new units per 1000 residents.  The vacancy rate for the municipality, in 2010, was 3.39%.  In 2011, single family homes made up 70.8% of the total housing in the municipality.
The historical population is given in the following chart:
Gadmen