The mishap occurred in Dendulur Mandal when the auto carrying six people was on its way to Satyanarayanapuram where the lorry was parked.
Driving in a rush, the autorickshaw driver rammed the vehicle into the lorry from the rear, resulting in the death of three persons on the spot, Eluru deputy superintendent of police (DSP) Sarita said.
However, the auto and lorry driver both escaped unhurt, she said.
The deceased were identified as K Prabhakar Rao (40), M Ramu (42) and S Srinivasa Rao (45), police said.