In November 2006 and with his contract set to expire at the end of the 2006–07 season, McCormack handed in a transfer request, before rejoining Championship club Southend United on loan on 18 November 2006, initially until 1 January 2007, with a view to a permanent move. After an impressive first month of his spell, assistant manager Paul Brush confirmed on 11 December that McCormack would transfer to the club permanently and he subsequently signed on a two-and-a-half-year contract. In what remained of the 2006–07 season, McCormack made 26 appearances and scored three goals, but he was unable to prevent Southend's relegation to League One.