As of the census of 2000, there were 36,929 people, 13,502 households, and 9,086 families residing in the city. The population density was 1,037.0/km² (2,686.5/mi²). There were 13,957 housing units at an average density of 391.9/km² (1,015.3/mi²). The racial makeup of the city was 62.92% White, 8.67% African American, 0.87% Native American, 7.02% Asian, 0.13% Pacific Islander, 15.61% from other races, and 4.77% from two or more races. Hispanic or Latino of any race were 35.24% of the population.

There were 13,502 households out of which 35.4% had children under the age of 18 living with them, 46.4% were married couples living together, 15.4% had a female householder with no husband present, and 32.7% were non-families. 26.0% of all households were made up of individuals and 8.8% had someone living alone who was 65 years of age or older. The average household size was 2.71 and the average family size was 3.29.

In the city the population was spread out with 27.4% under the age of 18, 8.0% from 18 to 24, 34.0% from 25 to 44, 20.2% from 45 to 64, and 10.4% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 92.2 males. For every 100 females age 18 and over, there were 87.6 males.

The median income for a household in the city was $45,375, and the median income for a family was $49,703. Males had a median income of $41,039 versus $32,259 for females. The per capita income for the city was $21,686. About 9.7% of families and 13.1% of the population were below the poverty line, including 18.3% of those under age 18 and 9.7% of those age 65 or over.

Notable residents

• Jim and Rose Leverton, Own Concept Design Productions
• Dicky Barrett, frontman, Mighty Mighty Bosstones, late night TV announcer
• Behrick, a golfer
• Mary Ford, vocalist and guitarist
• Jim Fuller, guitarist for The Surfaris (of "Wipeout" fame)
• Prince Gomolvilas a playwright
• Dean R. Hirsch, president of World Vision International
• Corky King, founder of Summum.
• Scott Land a puppeteer/actor
• Mildred Lapson[1], painter
• Upton Sinclair, author
• Jacob Smith, actor
• William A. Spinks (1865–1933), champion carom billiards pro, co-inventor of modern billiards cue chalk, oil investor, and flower and avocado farmer (developer of the Spinks avocado cultivar); also maintained a home and farm in nearby Duarte

Education

Monrovia High School gained a highly creditable rating in its early history. The first school in Monrovia was built in 1887. It was located where Monroe School now stands, and housed the entire elementary and high school student body. A new high school on the property now occupied by Clifton Middle School was erected in 1905, and in 1912 was greatly expanded by the addition of new buildings. In 1928 a high school to serve the communities of Monrovia, Arcadia and Duarte was built. The same structure now serves only Monrovia students, as the elementary and high school district were unified into one district in 1961. The district now has one high school, one continuation school, two middle schools and five elementary schools, and is part of the Citrus Community College District. There are also three parochial schools in Monrovia.

Monrovia, California's schools are:

• Bradoaks Elementary School, a California Distinguished School K-5, 930 E. Lemon
• Calvary Road Baptist Academy, K-12, 319 W. Olive
• Canyon Early Learning Center, public pre-K, 1000 South Canyon
• Canyon Oaks High School (public alternative), 7-12, 930 Royal Oaks Drive
• Carden of the Foothills, K-8, 429 Wild Rose
• Church of Nazadent, K-6 303 W. Colorado
• Clifton Middle School, a California Distinguished School 6-8, 226 S. Ivy
• First Lutheran School, pre-K-8, 1323 South Magnolia
• First Presbyterian Church Preschool, 101 E. Foothill Blvd.
• Immaculate Conception School, K-8, 726 Shamrock
• Mayflower Elementary School, a California Distinguished School K-5, 210 North Mayflower
• Monroe Elementary School, a California Distinguished School K-5, 402 W. Colorado
• Monrovia Community Adult School 920 South Mountain
• Monrovia High School 9-12, 845 W. Colorado Boulevard
• Monrovia Mountain School, public Alternative K-8, 950 S. Mountain Avenue
• Mt. Sierra College Trade College
• Plymouth Elementary K-5, 1300 Boley Street
• Santa Fe Middle School 6-8, 148 W. Duarte Road
• Serendipity Early Care and Education Center, K, 940 W. Duarte Road
• Wild Rose Elementary, A California Distinguished School K-5, 232 Jasmine