Bangor University has confirmed it will close its chemistry department and jobs will also be lost in other departments.
The university, among the oldest in Wales, blamed financial pressures, competition and falling students numbers for the cuts.
Up to 60 jobs were under threat after the university announced in October it had to cut £5m.
Bangor was the only university offering people the chance to study chemistry in Welsh.
There will also be job losses in both finance and corporate services as well as in the schools of Education and Human Development, Medical Sciences, Health Sciences, and Sport, Health and Exercise Sciences.
Students held protests against the proposed cuts during a three-month consultation process.
There are 23 first-year students currently enrolled on the single-honours Bachelor of Science chemistry course, compared with 61 in 2015-16.
"After careful consideration, Bangor University has reluctantly taken the difficult decision to discontinue chemistry degrees," it said in a statement.
"This means that no new students will be enrolled on chemistry programmes for the 2019-20 academic year."
Existing students have been assured they will be able to graduate.
Student union leaders had claimed money could be saved by cutting the salaries and expenses of the university's higher-earners.
However interim vice-chancellor Professor Graham Upton called the job losses "necessary".
He said: "We will do everything we can to support the staff and students affected.
"We will also be working with external funders, project partners and companies to complete research projects and studentships."
President of the Welsh Union at Bangor University, Gethin Morgan, said it was a "hard decision" to discontinue the subject.
He said: "UMCB will continue to work with the university to ensure that our current students get the best experience possible. Our focus is minimizing the disruption to our current students."