The event started at noon at the Beachlands Speedway and involved competitors of all ages getting covered in mud as they cycled through the course.
Event organiser Matt Dunstan said the wet and dreary day was perfect cyclocross weather as getting covered in mud was all part of the fun.
"Everybody gets mixed in and muddy," he said.
The event was described as complete organised chaos.
Competitors rode their bicycle in a 2km loop as fast or as slow as they wanted.
The mud-caked track ran through the surrounding bush and around the speedway, with 65 riders whizzing around and flinging mud over everyone and everything.
"It’s all for fun, the loop means everybody gets mixed in and makes it less of a competition," Mr Dunstan said.
Despite this, three riders battled it out at the front for the first few laps, before a mud-covered Jake Remon gained a comfortable lead and took the top spot.
In second and third place were James Howard and Dimitri Demoshev.
The event was organised by Bike House Dunedin in collaboration with Mountain Bike Otago.
Cyclists will be back at it next Sunday for the second round of races.
