Using the NICHD Early Childcare dataset (N = 1281), this study examined whether infant temperament and the amount of time infants spend in nonmaternal care independently predict (1) the likelihood that they seek comfort from their mother when needed and (2) placement in a particular subgroup of infant-mother attachment patterns. Mothers reported the number of hours their infant spent in nonmaternal care each month and their infant's difficulty adapting to novel stimuli at 6 months. The degree to which 15-month-old infants seek comfort from their mother during reunion episodes in the Strange Situation was observed using two behavioral scales ("proximity seeking" and "contact maintaining"). Their average score forms the outcome variable of "proximity-seeking behavior." The other outcome variables were the subgroups of infant-mother attachment patterns: two sub-groups for insecure babies (resistant and avoidant) and four subgroups for secure babies (B1, B2, B3, and B4). Easy adaptability to novel stimuli and long hours of nonmaternal care independently predicted a low level of proximity-seeking behavior. These predictors also increased the likelihood of an insecure infant being classified as avoidant (vs. resistant). A secure infant with these same predictors was most likely to be classified as B1, followed by B2, and then B3, with B4 being the least likely classification. Although previous studies using the NICHD dataset found that hours of nonmaternal care had no main effect on infants' attachment security (vs. insecurity), this study demonstrates that hours of nonmaternal care predict the subcategories of infant-mother attachment. (author abstract)