The quake struck at 7:22 am local time (0308GMT) Saturday in the town of Dorood, causing damage to residential buildings.
The report said 25 of those injured had to remain hospitalized. The others were released after treatment for minor injuries.
The quake caused panic and residents fearing aftershocks left their homes.
A local rescue services official told the Mehr news agency that "most of the damage was caused to two residential buildings."
Two more light earthquakes hit Iran overnight Saturday. A magnitude-4.2 quake struck in the country's northwest region at around 2:30 am, and two hours later a magnitude-4 tremor hit the same area. There were no reports of injury in either earthquake.
Iran is located on seismic fault lines and on average experiences at least one small earthquake a day.
A magnitude-6.6 quake flattened the historic southeastern city of Bam in 2003, killing 26,000 people.