Zwischbergen has a population (as of December 2018) of 77.
 As of 2008, 12.6% of the population are resident foreign nationals.
 Over the last 10 years (1999–2009 ) the population has changed at a rate of -35.4%.
 It has changed at a rate of -24.1% due to migration and at a rate of -11.4% due to births and deaths.

Most of the population (as of 2000) speaks German (69 or 88.5%) as their first language, Italian is the second most common (4 or 5.1%) and Spanish is the third (3 or 3.8%).
 There is 1 person who speaks French.

As of 2008, the gender distribution of the population was 58.8% male and 41.2% female.
 The population was made up of 54 Swiss men (52.9% of the population) and 6 (5.9%) non-Swiss men.
 There were 40 Swiss women (39.2%) and 2 (2.0%) non-Swiss women.
 Of the population in the municipality 48 or about 61.5% were born in Zwischbergen and lived there in 2000.
 There were 14 or 17.9% who were born in the same canton, while 7 or 9.0% were born somewhere else in Switzerland, and 8 or 10.3% were born outside of Switzerland.

The age distribution of the population (as of 2000) is children and teenagers (0–19 years old) make up 25.6% of the population, while adults (20–64 years old) make up 59% and seniors (over 64 years old) make up 15.4%.
 As of 2000, there were 31 people who were single and never married in the municipality.
 There were 36 married individuals, 7 widows or widowers and 4 individuals who are divorced.

As of 2000, there were 31 private households in the municipality, and an average of 2.3 persons per household.
 There were 9 households that consist of only one person and 3 households with five or more people.
 Out of a total of 33 households that answered this question, 27.3% were households made up of just one person and there was 1 adult who lived with their parents.
 Of the rest of the households, there are 8 married couples without children, 8 married couples with children  There were 4 single parents with a child or children.
 There was 1 household that was made up of unrelated people and 2 households that were made up of some sort of institution or another collective housing.

In 2000 there were 10 single family homes (or 25.6% of the total) out of a total of 39 inhabited buildings.
 There were 16 multi-family buildings (41.0%), along with 10 multi-purpose buildings that were mostly used for housing (25.6%) and 3 other use buildings (commercial or industrial) that also had some housing (7.7%).

In 2000, a total of 31 apartments (41.9% of the total) were permanently occupied, while 28 apartments (37.8%) were seasonally occupied and 15 apartments (20.3%) were empty.
 The vacancy rate for the municipality, in 2010, was 2.41%.

The historical population is given in the following chart:
Zwischbergen has a population (as of December 2018) of 77.  As of 2008, 12.6% of the population are resident foreign nationals.  Over the last 10 years (1999–2009 ) the population has changed at a rate of -35.4%.  It has changed at a rate of -24.1% due to migration and at a rate of -11.4% due to births and deaths.
Most of the population (as of 2000) speaks German (69 or 88.5%) as their first language, Italian is the second most common (4 or 5.1%) and Spanish is the third (3 or 3.8%).  There is 1 person who speaks French.
As of 2008, the gender distribution of the population was 58.8% male and 41.2% female.  The population was made up of 54 Swiss men (52.9% of the population) and 6 (5.9%) non-Swiss men.  There were 40 Swiss women (39.2%) and 2 (2.0%) non-Swiss women.  Of the population in the municipality 48 or about 61.5% were born in Zwischbergen and lived there in 2000.  There were 14 or 17.9% who were born in the same canton, while 7 or 9.0% were born somewhere else in Switzerland, and 8 or 10.3% were born outside of Switzerland.
The age distribution of the population (as of 2000) is children and teenagers (0–19 years old) make up 25.6% of the population, while adults (20–64 years old) make up 59% and seniors (over 64 years old) make up 15.4%.  As of 2000, there were 31 people who were single and never married in the municipality.  There were 36 married individuals, 7 widows or widowers and 4 individuals who are divorced.
As of 2000, there were 31 private households in the municipality, and an average of 2.3 persons per household.  There were 9 households that consist of only one person and 3 households with five or more people.  Out of a total of 33 households that answered this question, 27.3% were households made up of just one person and there was 1 adult who lived with their parents.  Of the rest of the households, there are 8 married couples without children, 8 married couples with children  There were 4 single parents with a child or children.  There was 1 household that was made up of unrelated people and 2 households that were made up of some sort of institution or another collective housing.
In 2000 there were 10 single family homes (or 25.6% of the total) out of a total of 39 inhabited buildings.  There were 16 multi-family buildings (41.0%), along with 10 multi-purpose buildings that were mostly used for housing (25.6%) and 3 other use buildings (commercial or industrial) that also had some housing (7.7%).
In 2000, a total of 31 apartments (41.9% of the total) were permanently occupied, while 28 apartments (37.8%) were seasonally occupied and 15 apartments (20.3%) were empty.  The vacancy rate for the municipality, in 2010, was 2.41%.
The historical population is given in the following chart:
Zwischbergen