Lt-Col Ronel Otto said the ranger of the private game farm heard shots being fired around 09:00 on Friday and called the police.
"Together they traced the suspects on foot and four suspects were found on the farm."
Two men ran away but the other two were arrested. A rhino horn, hunting rifle, two projectiles and an axe were found in their possession.
The men, from Mozambique and South Africa, were expected to appear in the Hoedspruit Magistrate's Court on Monday.
Otto said the search for the men's accomplices continued