The objectives of this study were: 1) to describe relationships among regulatory behaviors, affect, attention and cardiorespiratory reactivity in 3 mo. term and preterm infants, during behavioral assessment, and 2) to determine if regulatory capacities in the same infants at 1 mo. predict behavior during temperament assessment at 3 mo. Subjects were 82 term and preterm infants at three months corrected age: 31 healthy full-term (FT), 23 healthy preterm (HPT), and 28 sick preterm (SPT). Preterms were born at <34 weeks gestation, and <1750 g. The Brazelton Scale (NBAS) was administered at 1 mo. Regulatory behaviors were coded from videotape during a face-to-face/still-face (FTF) procedure, and temperament assessment at 3 mo. EKG was monitored continuously both during NBAS and three month assessment. Respiratory sinus arrhythmia (RSA) was calculated from the heart period. EKG and RSA were synchronized with coded behaviors for time-matched analysis. Results for all infants showed that at 3 mo., more disengagement (gaze aversion) was related to more positive affect (r =.55; p<.001), higher attention (r =.38; p<.01), and higher RSA (r =.22; p<.05), and more disengagement was associated with more positive affect during the stranger episode of FTF (r =.40; p<.01). These results suggest that the ability to withdraw from social interaction can facilitate sociability and attention. The FT group demonstrated the strongest association between disengagement and positive affect (r=.68; p<.001), followed by HPT (r=.51; p<.05) and SPT(r=.46; p<.05), suggesting that FT infants are better able to utilize withdrawal from interaction as a regulatory strategy. Higher NBAS scores at 1 mo. were related to more disengagement at 3 mo. for all groups (all p<.001). Higher heartrate (HR) during the NBAS was associated with more thumbsucking (r =.29; p<.05) and more foot bracing (r =.35; p<.01) at 3 mo. Infants with higher scores on behavioral regulation at 1 mo. use disengagement for self-regulation at 3 mo. Infants with higher physiological arousal at one month use more active strategies for self-regulation at three months of age.