Affoltern has a population (as of ) of . , 25.5% of the population was made up of foreign nationals. Over the last 10 years the population has grown at a rate of 9.8%. Most of the population () speaks German (82.5%), with Italian being second most common (5.0%) and Serbo-Croatian being third (3.7%). In the 2007 election the most popular party was the
SVP which received 37.5% of the vote. The next three most popular parties were the
SPS (17.3%), the
FDP (11.4%), and the
CSP (11.3%). The age distribution of the population () is children and teenagers (0–19 years old) make up 25.2% of the population, while adults (20–64 years old) make up 62.4% and seniors (over 64 years old) make up 12.3%. In Affoltern about 71% of the population (between age 25–64) have completed either non-mandatory
upper secondary education or additional higher education (either university or a
Fachhochschule). Affoltern has an unemployment rate of 2.8%. , there were 85 people employed in the
primary economic sector and about 33 businesses involved in this sector. 1238 people are employed in the
secondary sector and there are 126 businesses in this sector. 3533 people are employed in the
tertiary sector, with 441 businesses in this sector. The historical population is given in the following table: ==Transport==