The calculated distance (air line) between Sremska Mitrovica and Zrenjanin is approximately 47 miles respectively 75 kilometers.
By car or train, the actual journey to Zrenjanin is certainly longer, as only the direct route (as the crow flies) between Sremska Mitrovica and Zrenjanin has been calculated here.
Air line (approximately)
75 kilometers
41 nautical miles