The present study validates a new procedure that combines continuous measures of proximity (Ubisense) and vocalization (LENA) into measures of peer social interaction. The data were collected from 4 boys and 5 girls (ages 2-3 at the outset) on 8 separate days (3-4 hours per day) over the course of an academic year. Teacher reports of friendship were positively correlated with continuous measures of dyadic social interaction (i.e., the amount of time two children spent in proximity to one another, talking). Self-reports of reciprocated friendship were marginally correlated with continuous measures of dyadic social interaction, but only in the spring semester (when children were older and their reports of friendship more reliable). At the individual level, peer nominations of likeability, and teacher ratings of sociability and withdrawal were correlated with continuous measures of social interaction (i.e., the amount of time a child spent in proximity to other children, talking). [This is the online version of an article published in "European Journal of Developmental Psychology" (ISSN 1740-5629).]