The new flight to the Ukrainian capital, which will operate five times a week, was granted approval after a hearing at the UK Civil Aviation Authority (CAA).
British Airways had also launched a bid to operate the flight, which is part of an agreement between the UK and Ukrainian governments to allow a greater frequency of flights between the two countries.
Commenting on the service, Nigel Turner, bmi group chief executive officer, said he was "delighted" by the CAA’s decision.
"Bringing in new competition from bmi rather than allocating the capacity to the incumbent carrier will clearly produce more benefit to consumers, bring prices down and provide an improved product offering to both business and leisure passengers," he said.
Mr Turner added that the flight would be a "boon" to point-to-point passengers travelling between London and Kiev.
bmi last week doubled the number of flights it operates between Heathrow and Saudi Arabian capital Riyadh.