In the first incident, two women were killed and three others injured when an ambulance collided with a truck in Gambhirpur area in Azamgarh district.
Rekha Rai (64) and Sushma (54) were killed on the spot in the incident, police said.
The three injured have been rushed to a hospital, where their condition was stated to be stable.
In a similar incident, an ailing woman was killed and six others were injured when an ambulance collided with a tanker in Jafrabad area in Jaunpur.
Munni Devi (45), who was being taken to a hospital in Varanasi in the ambulance, was killed on the spot, officials said.
The six injured, including two women, were admitted to a hospital, where their condition was stated to be stable.