Every year in France, nearly 50 infants live in a prison nursery with their mother. According to French law, infants can live with their mother in the prison nursery until they reach 18 months of age. The international community is concerned about the lack of validated social, medical and legal data on these infants living in prison. This was a retrospective and descriptive study. Medical and paramedical files of the General Council of Île-et-Vilaine, France, were studied. Every infant born between 1998 and 2013 while their mother was in prison were included. Fifty-four files were collected. The average length of stay was 6.2 months (n=54). The type of the mother's prison sentence was property damage in 40 % of cases, personal injury in 51.1 % of cases and both in 8.9 % of cases (n=45). The length of the mother's imprisonment was on average 45 months, ranging from 3 to 216 months (n=34). After prison, 42.9 % of the infants were placed in foster care and 57.1 % resided with their family (n=42). This child-mother incarceration could be an opportunity for positive intergenerational paramedical, medical and social services. The lack of data and problems collecting data restrict our knowledge of these families. This should motivate a national follow-up for these children.