Background: A significant proportion of pregnancies occurring in Metropolitan Santiago are unplanned and unwanted. It is reasonable to postulate that the frequency of unwanted children must be high. Aim: To measure the frequency of unwanted children in newborns of a public hospital of Santiago. Material and methods: In a period of fourteen months a score assigning survey to detect unwanted children was applied, after birth, to 741 women delivering at San Juan de Dios Hospital in Metropolitan Santiago. Women whose newborns were hospitalized or bad congenital malformations were excluded from the survey. Results: Forty children (5.4%) scored as unwanted while 52 (7%) qualified as being in a doubtful situation. When compared to desired children, unwanted infants bad a lower frequency of suitable pregnancy controls (p <0.0002) and a higher incidence of mothers declaring bad relations with children's father (p <0.0002). A trend towards higher frequency of single mothers (p: 0.044) was observed. A lower frequency of first born children (p: 0.017) and a higher frequency of children born in the fourth place, was observed among unwanted newborns (P <0.002). Conclusions: In the last 15 years, previous studies, carried out with similar methodologies, have showed a comparable frequency of unwanted children. These condition seems to be associated with poor pregnancy control, high birth order and bad relations with the child's father.