Computer science is the study of the theoretical and practical aspects of computer technology and computer usage. The department offers courses on a wide range of topics, many of which include a mathematical component. UC Santa Cruz offers both the bachelor of arts and bachelor of science degrees, as well as the master of science and doctor of philosophy degrees, in computer science. Besides offering instructional courses, the Computer Science Department engages in a substantial research program in which both advanced undergraduates and graduate students participate.

The Department of Computer Science (CS) offers B.A., B.S., M.S. and Ph.D. degrees. Areas of research include analysis of algorithms, artificial intelligence, pattern recognition and retrieval, machine learning, neural networks, computer graphics, computer animation, scientific visualization, computer and sensor vision, image processing, image synthesis, multimodal human-computer interaction, programming languages and environments, software engineering, Web and Internet engineering, real-time embedded systems, computer security, databases, parallel and distributed computation, operating systems, and storage systems.

In cooperation with other departments on campus, CS also offers a strong research group in bioinformatics, computational biology, biomolecular engineering, and human genome mapping. The CS department enjoys a close relationship with the Computer Engineering, Electrical Engineering, and Applied Mathematics and Statistics departments. Faculty members carry out joint research projects, supervise students, and teach courses for these departments. The M.S. degree requires either a master's thesis or an approved project and is usually completed in two years, although it is possible to complete the program in one year. The Ph.D. degree is usually completed in five years.

The bachelor of arts program at UCSC is designed to give students a solid grounding in both theoretical and practical topics in computer science, computer engineering, and mathematics, while leaving flexibility for a broad program of study including many courses outside of the sciences, or even for a double major in another discipline. The bachelor of science program is appropriate for students desiring a somewhat stronger concentration in the sciences, with more courses in computer science and computer engineering as well as courses in physics or chemistry; this program also allows for electives outside of the sciences. Because many courses in both programs have prerequisites, students leaning toward either program will enjoy greater scheduling flexibility if they begin some preparatory courses in their first year. The specific course requirements for each undergraduate degree are given below.

Applications of computer science are found in many other areas of study, from art and music to business and science. Thus, interdisciplinary activities are encouraged. For those students whose primary interest is in another area, a minor in computer science is offered.