The present study sought to analyze infant and maternal behavior both during the Strange Situation Procedure (SSP) and a free play session in a Korean sample (N = 87) to help understand whether mother-infant attachment relationships are universal or culture-specific. Distributions of attachment classifications in the Korean sample were compared with a cross-national sample. Behavior of mothers and infants following the two separation episodes in the SSP, including mothers' proximity to their infants and infants' approach to the caregiver, was also observed, as was the association between maternal sensitivity observed during free play session and infant security. The percentage of Korean infants classified as secure versus insecure mirrored the global distribution, however, only one Korean baby was classified as avoidant. Following the separation episodes in the Strange Situation, Korean mothers were more likely than mothers in Ainsworth's Baltimore sample to approach their babies immediately and sit beside them throughout the reunion episodes, even when their babies were no longer distressed. Also, Korean babies less often approached their mothers during reunions than did infants in the Baltimore sample. Finally, the link between maternal sensitivity and infant security was significant. The findings support the idea that the basic secure base function of attachment is universal and the SSP is a valid measure of secure attachment, but cultural differences in caregiving may result in variations in how this function is manifested.