The first provision for state-wide registration of births and deaths was enacted July 1, 1883, and was repealed in 1893. Registration ceased until 1910. The Missouri State Archives maintains a searchable database of birth and death records  prior to 1910 and post 1910 to 1957.
The Missouri Department of Health, Bureau of Vital Records  provides information about birth, death, marriage, and divorce records for Missouri and how to obtain certified copies.
For Jackson County, birth records may be obtained from:
The Bureau of Vital Records
P.O. Box 570
Jefferson City, MO 65102
If you were born in the State of Missouri after 1920, birth certificates are also available at the Jackson County Health Department in Independence, Missouri, located at 313 S. Liberty. For directions and pricing information call the Health Department at (816) 404-6415.
If you were born in Kansas City, Missouri, a copy of your birth certificate is available from:
2400 Troost, Suite 1200
Kansas City, MO 64108
The Missouri Valley Room has death records from the Office of Vital Statistics, Kansas City Health Department for Kansas City, Missouri, covering the period August 3, 1874, through December 31, 1909.
These records list the following:
In addition, there is a set of records commonly referred to as "The Dead People Files." These are records from the Kansas City Health Department's Office of Vital Statistics, dating from ca.1910 through ca.1985. They provide data about persons who died outside of Kansas City but were buried here. The specific information includes:
Death records on microfilm in the Missouri Valley Room from the Missouri State Archives include (some overlap):
Birth records for Jackson County on microfilm from the Missouri State Archives include (some overlap):
Selected nineteenth-century birth and death information for other counties may be found by searching the Library's online catalog  using the county name and birth or death in the search box.
Jackson County Department of Records  has a searchable database of marriages for the county. If the person your searching is not found in the database, and you know they were married in Jackson County, the license may have been purchased in a different Missouri county, and therefore will not be in this database.
Indexes to Jackson County marriage records in the Missouri Valley Room from the Missouri State Archives (on microfilm) include:
For divorce records in Jackson County, one must write for the records – there is no online searching. Call 816-881-3913 for current fees.
Judicial Records Department
Jackson County Courthouse
415 East 12th Street
Kansas City, MO 64106