The suicide bomber, who was riding a motorcycle, attacked a military vehicle carrying civilians.
A police official, who spoke to Reuters on condition of anonymity, confirmed the casualty figure.
Pakistan is currently carrying out its first census since the last was held in 1998. The military is helping the Civilian Bureau of Statistics carry out a door-to-door survey of the population.
Aljazeera reports that the vehicle that was carrying the census team was approached on the outskirts of Lahore by the suicide bomber who was riding a motorcycle.
The bomber detonated the explosive, killing two civilians who were part of the census team, the report said.