Prior studies on mothers and infants have explored a great many individual variations. To date, however, the empirically based meaningfulness of these variations is quite limited. The current study attempts to achieve a relatively comprehensive empirical description of the mother-infant relationship at the age of 6 months, with special focus on possible correlates of infant developmental competence. 168 mother-infant pairs contributed data on a wide variety of measures, including the following categories: (a) observed interactions, at home and in the laboratory; (b) mother perception of the infant's temperament, mother personality, social support, and family adjustment to the new baby; (c) infant performance on the Bayley test; and (d) background variables such as birth order and economic status. Relationships among the various measures were modeled with factor analytic methods and interpreted in connection with current research issues. The most important findings are the following: (1) The main factor is widely generalizable dimension in maternal behavior of warm, responsive interaction with the infant. (2) Some elements of this main factor overlap with another factor indexing the extent to which mother impresses observer as educationally stimulating. Social class was associated with this teaching factor, but not with the first, more affection- and play-oriented, dimension. (3) Mother perceptions of difficult temperament in the infant were associated with objectively observed crying and fussing but were essentially independent of the major dimensions of maternal behavior. (4) Observed active and happy behaviors of the infant were somewhat related to normative status on the Bayley test, but neither active and happy behavior nor Bayley score correlated with the important dimensions of maternal behavior.