Ostermundigen has a population (as of December 2018) of 17,751.
As of 2010, 24.4% of the population are resident foreign nationals.
Over the last 10 years (2000–2010) the population has changed at a rate of 1.3%.
Migration accounted for 0.3%, while births and deaths accounted for 1.1%.

Most of the population (as of 2000) speaks German (12,677 or 82.0%) as their first language, Italian is the second most common (677 or 4.4%) and French is the third (372 or 2.4%).
There are 18 people who speak Romansh.

As of 2008, the population was 48.2% male and 51.8% female.
The population was made up of 5,440 Swiss men (35.2% of the population) and 2,007 (13.0%) non-Swiss men.
There were 6,238 Swiss women (40.4%) and 1,753 (11.4%) non-Swiss women.
Of the population in the municipality, 3,234 or about 20.9% were born in Ostermundigen and lived there in 2000.
There were 5,881 or 38.1% who were born in the same canton, while 2,400 or 15.5% were born somewhere else in Switzerland, and 3,237 or 20.9% were born outside of Switzerland.

As of 2010, children and teenagers (0–19 years old) make up 18.1% of the population, while adults (20–64 years old) make up 62.1% and seniors (over 64 years old) make up 19.8%.

As of 2000, there were 6,037 people who were single and never married in the municipality.
There were 7,480 married individuals, 900 widows or widowers and 1,035 individuals who are divorced.

As of 2000, there were 2,918 households that consist of only one person and 255 households with five or more people.
In 2000, a total of 7,176 apartments (93.1% of the total) were permanently occupied, while 396 apartments (5.1%) were seasonally occupied and 133 apartments (1.7%) were empty.
As of 2010, the construction rate of new housing units was 2.9 new units per 1000 residents.
The vacancy rate for the municipality, in 2011, was 0.73%.

The historical population is given in the following chart:
Ostermundigen has a population (as of December 2018) of 17,751. As of 2010, 24.4% of the population are resident foreign nationals. Over the last 10 years (2000–2010) the population has changed at a rate of 1.3%. Migration accounted for 0.3%, while births and deaths accounted for 1.1%.
Most of the population (as of 2000) speaks German (12,677 or 82.0%) as their first language, Italian is the second most common (677 or 4.4%) and French is the third (372 or 2.4%). There are 18 people who speak Romansh.
As of 2008, the population was 48.2% male and 51.8% female. The population was made up of 5,440 Swiss men (35.2% of the population) and 2,007 (13.0%) non-Swiss men. There were 6,238 Swiss women (40.4%) and 1,753 (11.4%) non-Swiss women. Of the population in the municipality, 3,234 or about 20.9% were born in Ostermundigen and lived there in 2000. There were 5,881 or 38.1% who were born in the same canton, while 2,400 or 15.5% were born somewhere else in Switzerland, and 3,237 or 20.9% were born outside of Switzerland.
As of 2010, children and teenagers (0–19 years old) make up 18.1% of the population, while adults (20–64 years old) make up 62.1% and seniors (over 64 years old) make up 19.8%.
As of 2000, there were 6,037 people who were single and never married in the municipality. There were 7,480 married individuals, 900 widows or widowers and 1,035 individuals who are divorced.
As of 2000, there were 2,918 households that consist of only one person and 255 households with five or more people. In 2000, a total of 7,176 apartments (93.1% of the total) were permanently occupied, while 396 apartments (5.1%) were seasonally occupied and 133 apartments (1.7%) were empty. As of 2010, the construction rate of new housing units was 2.9 new units per 1000 residents. The vacancy rate for the municipality, in 2011, was 0.73%.
The historical population is given in the following chart:
Ostermundigen