Both. Click here: British, Canadian and American Spelling
which is correct: recognise or recognize?
Thanks. I cannot open that site in the office but I understood.
Good English dictionaries (including the Oxford English Dictionary and Chambers) show 'recognized' as the main option with -ise as an alternative. This is certainly my preference. To suggest that ize is a US invention is incorrect. The 'z' was good enough for William Shakespeare (and I doubt if he was influenced by anyone over the Atlantic in the late 16th century!) so it's fine with me.