The SB-2 bombers were among the first aircraft that arrived in Spain from the USSR during the civil war. By October 1936, the Spanish Republican Air Force already had 31 aircraft of this type, and the total number of SB deliveries to Spain during the entire period of the armed conflict is estimated at about 170 – 200 copies. The Republicans gave them the nickname “Katyushka”. In the initial period of the war, these aircraft had superiority in speed and flight altitude over enemy fighters. However, the appearance of Bf 109 fighters in the skies of Spain changed the situation, since now they already had an advantage in speed, thereby depriving the SB-2 bombers of the main advantage. Insufficient defensive armament and the lack of protection of the fuel tanks of the Katyushas also made them too vulnerable to the new fighters who fought on the side of the Francoists. The first SB was shot down by a Bf 109 fighter on July 23, 1937, and subsequently the losses continued to grow. By the end of the war, about 20 of these aircraft remained in the Republican Air Force.