“This was CS50”: Yale ends largest computer science course
After a decade of partnership with Harvard, Yale’s CS50 course will no longer be offered starting in fall 2025 due to limited funding and an expanding computer science department.

Julia Levy, Contributing Photographer
“Introduction to Computing and Programming,” better known by its Harvard course code of “CS50,” will not be returning in fall 2025.
One of Yale’s largest computer science courses, jointly taught with Harvard University, was canceled during a monthly faculty meeting after facing budgetary challenges, according to Ozan Erat, the most recent Yale instructor for the course. However, administrators expect the computer science department’s expanding faculty size will allow students to take more specialized introductory courses in future semesters.
“I think Yale CS benefited from CS50 a lot,” Erat wrote. “I have met students who decided to get into CS after taking CS50 for fun in their first year. CS50 was a fun course.”
Since Yale started offering the course in 2015, CS50 has consistently seen enrollment numbers in the hundreds and was often the department’s largest class. While students primarily watched lectures via the course’s website, they attended in-person sections and office hours led by undergraduate learning assistants, or ULAs.
However, according to Erat, the original donation that made CS50 possible ended in June 2024, and the cost of employing so many ULAs for the course had become unsustainable.
“From the beginning we were using a generous gift from someone (I don’t know who) for many years, but that ended in June 2024,” Erat wrote. “[The School of Engineering and Applied Sciences] helped us covering our costs [in fall 2024], but we had to cut down on many things. Maintaining CS50 at Yale was becoming difficult.”
In 2022, after ULAs for the course threatened to strike for higher wages, the computer science department increased the weekly pay limit for CS50 ULAs from 7.5 hours to 10 hours. In 2023, the course instruction team introduced an artificial intelligence chatbot known as the “CS50 duck,” which served as a virtual learning assistant to supplement the course’s roughly 40 ULAs.
According to Erat, both of these developments posed challenges to CS50’s diminishing financial resources.
“We were also using lots of ULA force for this class,” Erat wrote. “Regular ULAs work for 7.5 hours, but we were paying our ULAs 10 hours’ worth of payment. Thanks to the CS50 duck, we had less students in office hours and the excessive amount of ULA force became another financial burden.”
According to Theodore Kim, the director of undergraduate studies in computer science, the end of CS50 is a reflection of broader changes in the department, including a wider range of students taking computer science courses and a faculty size that has more than doubled since 2015.
Kim pointed to newer introductory offerings such as “Python for Humanities and Social Sciences,” “AI for Future Presidents” and “C Programming Language and Linux.”
“We now have the people and expertise to bring more focused pedagogy to the specific interests of the students,” Kim wrote to the News. “Students can choose the course that best fits their needs, rather than trying to get what they want from one giant course.”
Kim also noted that, for students still interested in taking CS50, the course’s content is available for free online.
In an email to former CS50 ULAs, Erat wrote that the department will offer an “enhanced” version of the course “Introduction to Programming” for both the fall and spring semesters.
However, some students and staff are concerned the end of CS50 may reduce opportunities for new students from underrepresented communities to become involved in computer science.
“CS50 was the space within the department where I felt like I belonged,” Wini Aboyure ’25, a former CS50 ULA, wrote. “I do worry that without CS50, we will lose some of the diversity that it introduces into the major.”
While Yale shifts to more specialized computer science introductory courses, David Malan, who teaches CS50 at Harvard, will focus on a new partnership with the University of Oxford. However, Malan looks back on his partnership with Yale as a “perfect proof of concept” that higher education can be more collaborative.
“That two schools, rivals no less, could come together in this way educationally has been a remarkable thing,” Malan wrote to the News. “I don’t think the world needs just one course in computer science. But I don’t think we need thousands, each siloed within institutions.”The Yale Computer Science Department was founded in 1969.