It happened Thursday night at the Merced Estates Mobile Home Park on Gerard Avenue.
Investigators say 58-year-old Michael Mojica hit his 62-year-old neighbor in the back of the head with a wooden object.
The victim suffered a two-inch cut on his head. He was taken to the hospital for treatment.
Officers later arrested Mojica at his home. He was booked into the Merced County jail on charges of assault with a deadly weapon.