The victim Firoz Anam is a first-year student of economics.
The arrestees were identified as Rubel Hossain, son of Jahid Hossain of Talaimari area; Rakesh Hossain, son of Rifat Hossain of Shiroil area; and Pervez, son of Khorshed Ali of Mirzapur area. Police are yet to identify the other two.
Motihar police arrested three suspects while the Detective Branch arrested two others.
The mugging bid took place at a field near Shahid Habibur Rahman Hall. Firoz was accompanying one of his female friends to her residential hall when muggers riding motorcycles approached them.
They asked Firoz to hand over his mobile phone and wallet. When he refused to comply, they stabbed him and fled. Firoz was taken to Rajshahi Medical College Hospital. Doctors said he was out of danger.
Hafizur Rahman, officer-in-charge of Motihar Police Station, said Firoz filed an attempted murder case around 11pm.
Meanwhile, students of economics department blocked the Dhaka-Rajshahi Highway on Saturday noon protesting against the attack and demanded arrest of the snatchers.
They suspended their protest and gave the university five days to accept and implement their three demands, including ensuring security on the campus.