The effects of attachment style and presence of a romantic partner on psychophysiological responses to a stressful laboratory situation were examined in a sample of 34 college women involved in serious dating relationships. In two separate laboratory sessions, one with romantic partner present and one with partner absent, participants were led to anticipate a stressful situation. Heart rate and systolic and diastolic blood pressure levels were recorded during baseline and stress periods in each condition. Significant three-way interactions showed that both avoidant and anxious participants in the partner-present condition evinced elevated psychophysiological responses to the stressor (relative to baseline), in contrast to these groups in the partner-absent condition and secure and nonanxious participants in both conditions. Findings are compared to those of previous research on attachment-style differences in proximity-seeking behavior in a similar laboratory situation, and they are interpreted in terms of the approach-avoidance conflict experienced by insecure people when faced with a stressful situation in the presence of their romantic partners.