The event was due to take place at Harewood House in Leeds on Saturday (July 7) and Sunday (July 8), but has been scrapped due to the extreme weather.
Cher Lloyd, Matt Cardle and Texas were among the acts due to play tomorrow.
The Human League, Steps, Scouting For Girls and Sophie Ellis-Bextor had been lined up for Sunday's bill.
"It is with our deepest regret that due to the adverse weather conditions leading up to this event in conjunction with the extreme weather warning as issued by the met office for the weekend, we were left with no other decision than to abandon this weekends MFest," a statement read.
"This was a joint decision made between the promoter, the production team, health and safety and Harewood House. We sought advice from a number of agencies, including Leeds City Council before making the decision.
"The public's health and safety is of paramount concern, therefore it would be irresponsible to continue, however disappointed we all are."
Tickets will be refunded, information of which will be available on the website from Monday July 9.