This study was an initial exploration of the relationship between coordinated interpersonal timing and quality of mother-toddler attachment. Eleven primiparous white, middle class mothers and their children (8 males, 3 females) participated. Mothers averaged 32 years of age and toddlers averaged 18.10 months. A prerecorded dyadic free-play session was coded by an entirely automatic microanalytic technique using the Automatic Vocal Transaction Analyzer, which times the sequence of vocal sounds and silences in the interaction. Time-series regression was used to determine the extent of temporal coordination. Attachment security was measured by the mothers' completion of the Attachment Q-Sort. Results revealed that: (1) the higher the infants' pause coordination with their mothers, the less secure their relationships; (2) infants had a less secure attachment relationship to older mothers; and (3) mothers engaged in more coordination of their vocalizations with those of their older infants. (Contains 23 references.) (Author/KDFB)