The men and women were arrested by the anti-vice police in a park in the suburbs of the town of Babol as they were partying during the night, the daily Iran wrote on Thursday.
The report said that all 54 men and women were flogged inside the offices of the Ministry of Justice in Babol.
Co-ed parties are banned in Islamic Iran. Thousands of teenage boys and girls were arrested last year for taking part in similar parties. Some were flogged in public.
