As of the census of 2000, there were 483,924 people, 187,233 households, and 132,373 families residing in the county. The population density was 258 people per square mile (100/km²). There were 226,376 housing units at an average density of 121 per square mile (47/km²). The racial makeup of the county was 79.58% White, 13.54% Black or African American, 0.38% Native American, 0.93% Asian, 0.04% Pacific Islander, 3.82% from other races, and 1.71% from two or more races. 9.49% of the population were Hispanic or Latino of any race.
There were 187,233 households, of which 29.00% had children under the age of 18 living with them, 54.40% were married couples living together, 12.00% had a female householder with no husband present, and 29.30% were non-families. 24.10% of all households were made up of individuals, and 11.10% have someone living alone who was 65 years of age or older. The average household size was 2.52 and the average family size was 2.96.
In the county the population was spread out, with 24.40% under the age of 18, 8.30% from 18 to 24, 26.40% from 25 to 44, 22.50% from 45 to 64, and 18.30% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 96.30 males. For every 100 females age 18 and over, there were 93.10 males.
The median income for a household in the county was $36,036, and the median income for a family was $41,442. Males had a median income of $31,396, versus $22,406 for females. The per capita income for the county was $18,302. 12.90% of the population and 9.40% of families were below the poverty line. Out of the total population, 19.10% were under the age of 18 and 8.10% were 65 or older.
As of July 1, 2005, the U.S. Census Bureau estimated the county had 542,912 residents, making it the ninth most populous county in Florida.