The aim of the 10K run in Regent's Park today is to enable families and friends to remember their missing loved ones and to raise funds for the charity's 24 hour phone line.
Among those taking part will be Missing family representatives Peter Lawrence, father of missing Claudia Lawrence, and Rachel Elias, sister of missing Manic Street Preacher Richey Edwards.
An estimated 250,000 people go missing in the UK every year.
The run begins at 9am on The Broadwalk, Chester Road, Regents Park.
More top news
A bright and sunny day tomorrow, but feeling distinctly cool and chilly tonight.
An ITV News London investigation has discovered the inquest will now be held at Westminster Coroner's Court.
The family court finalised the adoption as the criminal proceedings were still under way. The couple have vowed to fight for their child.