Bad Sassendorf is a municipality in the district of Soest, in North Rhine-Westphalia, Germany.

Mention was made of salt springs in the area appear in the 10th century, and were noted by the ambassador of the Caliphate of Cordoba to the court of Emperor Otto the Great in 973.

From the 19th century, the brine produced in the area was used for bathing and medicinal purposes, and the first therapy center or spa was opened in 1852.

They slept in freight train waggons on the track between Bad Sassendorf and Soest.

At the cemetery Bad Sassendorf a memorial plaque is installed on the burying place of the dead.