ABSTRACTAn account is given of the prevalence of fleas obtained at post‐mortem examination from dogs and cats in the Camden Town area of central London during the period 1972–1976. From a total of 193 dogs, fleas were collected from 20 2%. The following species were represented:Ctenocephalides felis felis, Ctenocephalides canisandOrchopeas howardi.Of a total of 316 cats, 56% harboured fleas, all of which were found to beCtenocephalides felis felis.The advantages of using cadavers rather than live cats and dogs for studies of this kind are noted and comparisons are made with the findings of other authors. The public health importance of the cat and dog flea in relation to human dermatitis is discus