This study evaluated the reaction to the still-face-related stress in 3 - to 6- month-olds infants. Twenty mothers and their infants were videotaped during the Tronick's Face-to-Face Still-Face paradigm (Tronick et al., 1978). Mothers were asked to play with their infants for 2 min, maintain a still, affectless expression for 2 min, and resume play for 2 min. The infants' responses were coded based on 3 dimensions: gaze, affect and behavior. Results indicated that infants reacted to the Still-Face with an increase in negative affect, gaze aversion and a reduction of social positive engagement ("still effect"). They also displayed a "reunion effect" as indexed by a carry-over of negative affect and behavior from the still-face to the reunion play. Furthermore, no correlation were found between infants' affect and regulatory behaviors during Still-Face paradigm and age and socio-economic status. Finally, no gender differences were found. Results are discussed in terms of early emotional regulation.