This aim of this study was to evaluate the effectiveness of an early intervention program to reduce paternal stress and increase fathering ability after a preterm infant's admission to the special care nursery and to influence paternal support for the mother and the father's attachment to the infant 1 month later. A historical comparison study was designed and an empowerment intervention strategy for the fathers of preterm infants was implemented. Forty-one fathers of preterm infants in the control group received routine care, and 41 fathers of preterm infants in the intervention group received an early fatherhood intervention program in the special care nursery. Both groups were followed 1 month after discharge. Fathers in the intervention group had significantly lower stress and higher fathering ability at their infant's discharge, provided better support to the mother in child-rearing, and had better father-infant attachment 1 month after discharge than fathers in the control group. Under cultural and hospitals' common practices, such an intervention can help the father to establish his fatherhood early and later enhance his supporting role to the mother and his relationship to the preterm infant. Nurses should include teaching childcare to fathers of preterm infants.