Based on concomitant time-series analyses, the results of this study support distinct social interaction correlates for the mood dimensions of negative affect (NA) and positive affect (PA). Participants (N = 25) completed structured diaries three times daily for 4 weeks assessing their PA, NA, and participation in five types of social interaction. A significant number of participants' data series evidenced significant positive correlations between PA and fun/active and necessary/informational types of social interaction, and between NA and arguing/confronting and receiving help/support, during synchronous diary periods. Providing help/support was not related to NA or PA. No hypothesized time-lagged relations between mood and social interaction variables were present suggesting that, if these associations exist, they may be at intervals shorter than the one third day recording frequency used in this study. Results are discussed in the context of research on mood, social interaction, and time-series analysis.