In the 1998 summer transfer window, Tomić was transferred to Italian club Roma. He struggled to become a first team regular under both Zdeněk Zeman and Fabio Capello. In July 2000, Tomić was loaned to Spanish club Alavés. He finally found his old form, helping the side reach the 2000–01 UEFA Cup final, eventually lost 4–5 to Liverpool in a remarkable game. Tomić subsequently returned to Roma, still failing to make an impact at the club. He was again loaned to Alavés in January 2003 until the end of the season. After failing to help them avoid relegation from La Liga, Tomić became a free agent after his contract with Roma expired. He later signed a one-year deal with Rayo Vallecano, another club that suffered relegation to Segunda División in 2003.