Middlesbrough wrap up Aliadiere deal
Boro agreed the fee with the Gunners and personal terms with the player some time ago but had to wait until he returned from holiday to finalise the transfer.
However, his opportunities at the Emirates Stadium were limited despite a major contribution to the Gunners' run to the Carling Cup final.
In all the former France Under-21 international started only 19 senior games and made a further 32 appearances as a substitute during his seven years with Arsenal, scoring nine goals.
Twelve of those starts came last season when, with 11 outings as a substitute, he scored four times, all of them in the League Cup.