Its report said 50g of processed meat a day - less than two slices of bacon - increased the chance of developing colorectal cancer by 18%.
Meanwhile, it said red meats were "probably carcinogenic" but there was limited evidence.
But the WHO said meat did also have health benefits.
Processed meats do cause cancer - WHO
26 October 2015
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Processed meats - such as bacon, sausages and ham - do cause cancer, according to the World Health Organization (WHO).
