This study examined father-infant and mother-infant relationships by observing infants and parents in their homes. The subjects were 20 infants, 10 boys and 10 girls, 7 and 8 months of age. Each infant was visited twice when both parents were at home. All visits were made by the same two persons: a male observer, who maintained a narrative account of infant and adult behaviors and a female visitor, who provided an alternative interactive partner for the child. Comparisons were made between the frequencies of affiliative- and attachment behaviors (including smiling, looking, vocalizing, reaching, approaching, and seeking to be held) which were directed by the infant toward each adult. Results of multivariate analyses showed a significant preference by infants for their fathers over their mothers and the visitor, and for their mothers over the visitor. When data were compared on the individual measures, neither parent emerged as a preferred attachment object but there was far more affiliative type interaction with father than mother. It was noted that fathers also engaged in more physically stimulating and unpredictable games. The author suggests that the prominence of play in the father-infant relationship helps to make the father a person with whom interaction is pleasurable, varied, and unpredictable. (Author/BRT)