Property of unknown value was on Saturday morning reduced to ashes at Marima market in Tharaka-Nithi County.
The dawn fire whose cause has not yet been established burnt down shops and residential houses in a one-storey building.
County fire engines battled the fire for more than four hours to stop it from spreading to a nearby petrol station and houses.
The county's emergency department manager Alex Mugambi said when they arrived at the scene around 4:40am the fire had already engulfed the entire building.
"I deployed two fire engines immediately I received the information and the officers did their best to put it out though it took long," said Mr Mugambi.
He said the two fire engines emptied fifteen tanks before the fire was completely put out.
Building materials in a warehouse were completely destroyed.
"The occupants were woken up by matatu operators who saw the fire, " said Mr Joh Mutegi, a local resident.