Police say the man landed on the balcony of the second floor of the building.
A senior PricewaterhouseCoopers Kenya manager died on Friday after he "fell off" from his 17th floor office in Westlands, Nairobi.
Police said the man landed on the balcony of the second floor of the Delta House building but did not die on impact.
He was pronounced dead on arrival at the Aga Khan Hospital.
Initial reports indicated that the deceased was a senior staff at the firm.
“Investigations over the matter have started and we shall get to the bottom of the matter,” Kilimani police chief Michael Muchiri said while confirming that the man succumbed to his injuries.
A crowd of curious onlookers milled around the building as they watched the man being rushed to hospital.
Mr Ibrahim Juma, who witnessed the incident, said that he heard a loud scream as the man came down before landing on the balcony.
“It is then that people rushed and helped him up before rushing him to hospital,” said Mr Juma.
In a statement, the firm said the incident was unfortunate and a big blow to the PwC family.
"Our collective grief and sense of loss at this time is profound; but it cannot compare to what his family must be feeling. Our hearts and prayers go out to them," said Mr Peter Ngahu, a regional senior partner.