This study explored stability and change in two aspects of infant temperamental behavior in a sample of 94 economically-disadvantaged rural Appalachian families. Regressions were used to predict Time 2 temperament for infants who increased and dereased in negative emotionality and positive/social behavior. Both infant and caregiving environment factors contributed to explaining change in first-year behavior. In this sample, maternal social support predicted more optimal change in infants' negative emotionality and positive/social behavior. Receiving public assistance and minor perinatal risk were associated with slower decline in negative emotionality and emergence of positive/social behavior.