As of the census of 2000, there were 20,017 people, 8,237 households, and 5,098 families residing in the city. The population density was 2,171.1 people per square mile (838.2/km²). There were 8,838 housing units at an average density of 958.6/sq mi (370.1/km²). The racial makeup of the city was 93.56% White, 0.30% African American, 1.30% Native American, 0.99% Asian, 0.10% Pacific Islander, 1.26% from other races, and 2.48% from two or more races. Hispanic or Latino of any race were 3.73% of the population.
There were 8,237 households out of which 28.9% had children under the age of 18 living with them, 46.2% were married couples living together, 11.9% had a female householder with no husband present, and 38.1% were non-families. 31.6% of all households were made up of individuals and 13.9% had someone living alone who was 65 years of age or older. The average household size was 2.32 and the average family size was 2.88.
In the city the population was spread out with 23.2% under the age of 18, 8.9% from 18 to 24, 26.5% from 25 to 44, 22.4% from 45 to 64, and 18.9% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 93.7 males. For every 100 females age 18 and over, there were 91.5 males.
The median income for a household in the city was $31,250, and the median income for a family was $40,172. Males had a median income of $32,624 versus $25,707 for females. The per capita income for the city was $17,082. About 11.0% of families and 15.1% of the population were below the poverty line, including 18.9% of those under age 18 and 9.2% of those age 65 or over.
Oregon Route 99 runs through downtown Roseburg as the main north-south arterial. Interstate 5 runs along the west side of the city, across the South Umpqua River from downtown.
Oregon Route 138 runs northwest from Roseburg to Elkton, Oregon, and generally east from Roseburg to its terminus at a junction with U.S. Route 97, just east of Diamond Lake and Crater Lake.
There is a Greyhound bus station with connecting service to Amtrak passenger rail service. The Central Oregon and Pacific Railroad freight railway runs through Roseburg. There are two public airports, Marion E. Carl Memorial Field at the north end of town and George Felt Airport to the west. Roseburg and surrounding communities are served by Umpqua Transit, a local bus service.