The Department of Mathematics was one of the first departments in the University of Missouri - St. Louis, initially known just as the Division of Sciences.  In the first year of the Residence Center of the University of Missouri (1960), there was a total of four full-time and eight part-time faculty in the division, one of who taught Math.  One of the first faculty members was Wayne McDaniel who was the first Chair starting in September 1960.  Initial course numberings were taken from the Columbia campus and the same textbooks were followed.  

In 1964, the Department of Mathematics and Accounting split from the Division of Sciences to establish itself as an independent department.  The first Chair was Emory Turner who later became UMSL Chancellor.  A year later in 1965, Mathematics split from Accounting and Ed Andalafte, who joined in 1964, became the Chair.  The department moved into Benton Hall for 1965-66 and started to plan for Clark Hall in 1966 - Clark was designated as a building for Mathematics and Languages.  The first Mathematics students graduated in Spring 1967.  In 1967-68, the department started to develop the Master’s program in Mathematics, which eventually started in 1971.  At that time, there were already 17 faculty members, with 7 in professorial rank and 6 holding a terminal degree.  

In 1968, the department got approval to add a degree in Computer Science, and submitted a list of Computer Science courses for the catalog in October 1971, and became the Department of Mathematics and Computer Science.  By December 1971, the department had graduated 100 majors.  By 1998, the department listed a Ph.D. degree in the offerings.  The department started a Master’s in Computer Science in 1999, and expanded the Ph.D. program to include a Computer Science option soon afterwards, followed by Statistics.  The department has steadily added more faculty in Computer Science and at present, there is almost an equal number of ranked faculty in Mathematics and Computer Science.

Starting around 2013, the department went through rapid modernization and expansion of its computer courses, culminated with five new certificates programs and recognition by HAS/NSA for excellence in cyber education. In 2016, Cezary Janikow became the first Computer Science faculty to Chair the entire department.