As of the 2000 Census, the city had a total population of 50,731. The city was named after 19th century U.S. congressman Oakes Ames of Massachusetts, who was influential in the building of the transcontinental railroad. Ames was founded near a location that was deemed favorable for a railroad crossing of the Skunk River. It is located roughly 30 miles (48 km) north of the state capital Des Moines. Two small rivers run through the town: the Skunk River and Squaw Creek.

Ames is home of Iowa State University of Science & Technology, a space grant college, at its founding, the state's (Morrill Act) land-grant university, formerly known as the Iowa State College of Agriculture and Mechanic Arts. Ames is the home of the closely allied U.S Department of Agriculture's National Animal Disease Center, and the main offices of the Iowa state Department of Transportation. State and Federal institutions are the largest employers in Ames.

Other area employers include a 3M manufacturing plant; Sauer-Danfoss, a hydraulics manufacturer; Barilla, a pasta manufacturer; Pella a window manufacturer; and Ball, a manufacturer of canning jars and plastic bottles.

As of the 2000 Census, there were 50,731 people, 18,085 households, and 8,970 families residing in the city. The population density was 908.1/km (2,352.3/mi). There were 18,757 housing units at an average density of 335.7/km (869.7/mi). The racial makeup of the city was 87.34% White, 7.70% Asian, 2.65% African American, 1.98% Hispanic American or Latino of any race, 0.15% Native American, 0.04% Pacific Islander, 0.76% from other races, and 1.36% from two or more races.

There were 18,085 households out of which 22.3% had children under the age of 18 living with them, 42.0% were married couples living together, 5.3% had a female householder with no husband present, and 50.4% were non-families. 28.5% of all households were made up of individuals and 5.9% had someone living alone who was 65 years of age or older. The average household size was 2.30 and the average family size was 2.85.

In the city the population was spread out with 14.6% under the age of 18, 40.0% from 18 to 24, 23.7% from 25 to 44, 13.9% from 45 to 64, and 7.7% who were 65 years of age or older. The median age was 24 years. For every 100 females there were 109.3 males. For every 100 females age 18 and over, there were 109.9 males.

A large number of Ames residents are university students. In 2004, for example, there were 26,390 students enrolled at Iowa State.

The median income for a household in the city was $36,042, and the median income for a family was $56,439. Males had a median income of $37,877 versus $28,198 for females. The per capita income for the city was $18,881. 20.4% of the population and 7.6% of families were below the poverty line. 9.2% of those under the age of 18 and 4.1% of those 65 and older were living below the poverty line.