Information is presented about 19 children, under age 7 years, from 17 families, whose mothers consistently gave fraudulent clinical histories and fabricated signs so causing them needless harmful medical investigations, hospital admissions, and treatment over periods of time ranging from a few months to 4 years. Episodes of bleeding, neurological abnormality, rashes, fevers, and abnormal urine were commonly simulated. Often the mothers had had previous nursing training and some had a history of fabricating symptoms or signs relating to themselves. Two children died. Of the 17 survivors, 8 were taken into care and the other 9 remained at home after arrangements had been made for their supervision. Study of these children and their families has enabled a list of warning signs to be compiled together with recommendations for dealing with suspected acts. The causes and the relationship of this form of behaviour to other forms of non-accidental injury, iatrogenic injury, and parental-induced illness are discussed.