Some 71 victims of Sunday’s twin blasts on the Thika Superhighway were taken to a hospital in Nairobi.
Ruaraka Uhai Neema Hospital clinical officer Ayub Torore said two died as they were undergoing treatment.
Mr Torore said 12 of the patients he attended to had suffered critical injuries and were referred to Kenyatta National Hospital (KNH) and other health institutions for specialised treatment.
Mr Kennedy Asoka, who was on a Mwiki-bound Mwi Sacco bus, said there was something odd about two young men who alighted before the bus left the terminus on Haile Selassie Avenue.
KNH received 16 women, 11 men and four children who were injured in the explosions.
One of the casualties, a woman, died on reaching the hospital, six were in critical condition while the rest were stabilised.
Addressing the Press outside the accidents and emergency ward, chief executive officer Lilian Tare said the referral hospital was doing all it could to help the injured.
Nurses were overwhelmed by the large number of patients in urgent need of critical treatment.