The European Union (EU) returned Kenya to the list of countries, which use high levels of pesticide in the horticultural produce, posing a threat to exports, the country's major source of foreign exchange.
The negative labelling comes just five months after Kenya was delisted in January, having partially complied with the requirements.
Blacklisting means that all the farm produce from Kenya must undergo mandatory time-consuming checks before they are allowed in the EU market.
"We have been listed having exceeded the required levels of residues,” says Ojepati Okesegere, chief executive of Fresh Producers Consortium of Kenya.
Kenya has over the years been fighting to be struck out of the list after it was first labelled in 2014.