Batov was selected to "volunteer" for service in the Spanish Civil War, under the nom de guerre Fritz Pablo. He first served as military adviser to the Hungarian communist Máté Zalka, who commanded the XII International Brigade defending the approaches to Madrid. He fought on the Teruel Front and was wounded twice and won his first Orders of Lenin and of the Red Banner as a result. After recovering, he fought at Jarama, alongside A.I Rodimtsev, at the Guadalajara and on the Aragon front, where he was wounded again.