Three people speak Romansh. Of the population in the municipality, 1,462 or about 19.5% were born in Bussigny and lived there in 2000. There were 2,673 or 35.6% who were born in the same canton, while 1,146 or 15.3% were born somewhere else in Switzerland, and 2,020 or 26.9% were born outside of Switzerland. In , there were 64 live births to Swiss citizens and 27 births to non-Swiss citizens, and in same time span there were 35 deaths of Swiss citizens and six non-Swiss citizen deaths. Ignoring immigration and emigration, the population of Swiss citizens increased by 29 while the foreign population increased by 21. There were 6 Swiss men who emigrated from Switzerland. At the same time, there were 92 non-Swiss men and 73 non-Swiss women who immigrated from another country to Switzerland. The total Swiss population change in 2008 (from all sources, including moves across municipal borders) was an increase of 85 and the non-Swiss population increased by 131 people. This represents a population growth rate of 2.8%. The age distribution, , in Bussigny is; 889 children or 11.1% of the population are 9 years old or younger and 1,006 children or 12.5% are between 10 and 19. Of the adult population, 1,116 people or 13.9% of the population are between 20 and 29 years old, 1,282 people or 16.0% are between 30 and 39, 1,336 people or 16.6% are between 40 and 49, and 1,031 people or 12.8% are between 50 and 59. The senior population distribution is 802 people or 10.0% of the population are between 60 and 69 years old, 384 people or 4.8% are between 70 and 79, 159 people or 2.0% who are between 80 and 89, and there are 28 people or 0.3% who are 90 and older.  , there were 3,194 people who were single and never married in the municipality. There were 3,612 married individuals, 259 widows or widowers and 433 individuals who are divorced.  , there were 3,062 private households in the municipality, and an average of 2.4 persons per household. There were 901 households that consisted of only one person and 199 households with five or more people. Out of a total of 3,114 households that answered this question, 28.9% were households made up of just one person and there were eight adults who lived with their parents.