As of the census of 2000, there were 29,349 people, 12,376 households, and 8,044 families residing in the borough. The population density was 1,483.0 people per square mile (572.6/km²). There were 13,159 housing units at an average density of 664.9/sq mi (256.7/km²). The racial makeup of the borough was 85.58% White, 8.29% African American, 0.14% Native American, 4.41% Asian, 0.04% Pacific Islander, 0.30% from other races, and 1.23% from two or more races. Hispanic or Latino of any race were 0.77% of the population.
There were 12,376 households out of which 25.8% had children under the age of 18 living with them, 52.7% were married couples living together, 9.7% had a female householder with no husband present, and 35.0% were non-families. 30.8% of all households were made up of individuals and 12.1% 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 2.89.
In the borough the population was spread out with 20.4% under the age of 18, 6.2% from 18 to 24, 27.4% from 25 to 44, 25.8% from 45 to 64, and 20.3% who were 65 years of age or older. The median age was 43 years. For every 100 females there were 88.5 males. For every 100 females age 18 and over, there were 84.8 males.
The median income for a household in the borough was $44,653, and the median income for a family was $53,474. Males had a median income of $41,100 versus $30,232 for females. The per capita income for the borough was $24,031. About 4.9% of families and 6.6% of the population were below the poverty line, including 9.4% of those under age 18 and 6.1% of those age 65 or over.
U.S. Highway 22 ran through Monroeville as a substantial business route. When the Parkway East (I-376) was extended east to connect to the Pennsylvania Turnpike, U.S. 22 was shifted to that road, and the original U.S. 22 stretch of William Penn Highway became Business U.S. 22.
Exit 57 (old Exit 6) of the Pennsylvania Turnpike is in Monroeville, with its interchange to Interstate 376.
Pittsburgh-Monroeville Airport is an infrequently used airport in ill repair at 40°27′08″N 79°46′29″W / 40.4522906°N 79.7747689°W / 40.4522906; -79.7747689. The airport has a single paved runway of 2280 feet (695 meters).
Several bus lines of the Port Authority of Allegheny County offer service to downtown Pittsburgh, and the Port Authority also has several park-and-ride lots located in Monroeville for bus commuters to Pittsburgh.