Comprised of approximately 90 to 100 musicians, ICSO is dedicated to performing symphonic repertoire from the baroque through the twentieth century, as well as contemporary works of our time. Led by Octavio Más-Arocas, the Symphony Orchestra presents 5 to 8 concerts per year.

Guest conductors have included Daniel Hege (Syracuse Symphony), Jose-Luis Novo (Annapolis Symphony), Carl Topilow (National Repertory Orchestra), and Larry Rachcleff (Rice University) among others, and the orchestra has collaborated with many of today's most prominent composers including Jennifer Higdon, Karel Husa, Michael Gandofli, Steven Mackey, Steven Stucky, Joan Tower, and Chen Yi. Former music directors include Pamela Gearhart, Grant Cooper, Jeffrey Grogan and Jeffery Meyer. Guest soloists who have appeared with the ICSO in recent seasons include Xak Bjerken (piano), Gilbert Kalish (piano) and Steven Mackey (electric guitar).

The ICSO has been distinguished with three consecutive ASCAP prizes for Adventurous Programming in the Collegiate Division by the League of American Orchestras: first prize in the 2010-2011 ASCAP Awards, second prize in 2011-12 and first prize in the 2012-13 awards. The ICSO was also a prize winner in two separate categories in the 2011 American Prize: Orchestral Performance and the Vytautas Marijosius Memorial Award for Programming, and again won 2nd place in the 2014 American Prize for Performance. The ensemble has performed to high acclaim in Avery Fisher Hall and Alice Tully Hall at Lincoln Center in New York, the Ithaca "Light in Winter" Festival, the New York State School Music Association Conferences, and New York University.

Membership in the IC Symphony Orchestra/Chamber Orchestra is open to all IC students by audition. Audition repertoire and excerpts are available online. Auditions take place during the first week of fall classes. Auditions must show a mastery of the material and an awareness of the musical context from which the excerpts are taken. In addition to the ICSO and ICCO, there is also the Ithaca College Sinfonietta which meets for two hours per week and presents one concert per semester.