Powered by two 1175 h.p. Daimler-Benz DB 601A-1 twelve-cylinder inverted vee engines, the sole Ro 58 was tested at Guidonia in early 1943 as a prototype two-seat long-range heavy fighter, corresponding to the German Zerstorer (Destroyer) class, exemplified by the Messerschmitt Bf 110. Manoeuvrability of the Ro 58 proved to be excellent for a twin-engined fighter, and quantity production was planned using the FIAT R.A.1050 R.C.58 Tifone engine, the license-built version 01 the Daimler-Benz unit. These plans were upset by the end of the war. The Ro 58 was an all-metal low-wing monoplane with twin fins and rudders. Armament consisted of five forward-firing Mauser MG 151 cannon, two of these in a ventral bulge which could be removed and replaced by a bomb rack, and one 12.7-mm. Breda-SAFAT defensive machine gun in the rear cockpit. Empty and loaded weights were 9590 lb. and 13,448 lb.
Performance included a maximum speed of 376 m.p.h. at 17,060 It., a cruising speed of 314 m.p.h., a service ceiling of 31,170 ft., and a range of 932 miles. Time to reach 19,680 ft. was 9 min. Dimensions were: span 43 ft. 11 1/2 in., length 32 ft. 5 3/4 in., height 11 ft. 7/8 in., and wing area 282 sq. ft.