Liver flukes as Clonorchis sinensis and the similar genus Opisthorchus felineus and O. viverrini are considered oncogenic as causing cholangiocarcinoma in about ten percent of cases where millions are infected in southeast Asia and Europe being endemic there and mostly asymptomatic but require treatment. Klatskin tumour is bile duct bifucational area carcinoma affection that is almost unique for these infections which comes by eating raw or undercooked fish and crabs. There has been strong evidence that both types of liver flukes are present in Egypt and Middle East being endemic since the snail first intermediate hosts is so many fresh water snails and risks are also, still similarly, to millions of humans, who require treatment to halt progression of disease in asymptomatic cases. This review aimed to clarify those types of flukes for health care workers and the public for better diagnosis, prevention and control, Also, to describe the main traits of C. sinensis and O. viverrini, their molecular biology and core carcinogenic mechanisms in a contrast pattern.