Aim: This preliminary longitudinal study examined timing features and type of interaction between infant boys and their mothers with attention deficit hyperactivity disorder (ADHD) symptoms. Method: Ten infants and their mothers with ADHD symptoms and 10 control dyads were video recorded at home during free play interactions when infants were 2-, 4-, 6-, and 9-month old. Microanalysis of the video recordings was carried out to assess synchronization, turn-taking, and type of interaction. Infants’ temperament was also assessed. Results: ADHD dyads showed shorter synchronization at 2 months and shorter duration of Joint Attention. Partial least squares regression analysis revealed that infant's ability for Joint Attention is predicted mainly by duration of maternal behavior as well as by earlier forms of communication, that is, protoconversations. Conclusion: The data from our preliminary study suggest that mothers with ADHD symptoms may have difficulties maintaining their behavior for enough time possibly due to the core symptoms of the disorder, that is, inattention, hyperactivity, and impulsivity. This maternal deficit seems to affect temporal coordination with their infants and maybe the development of more complex forms of interaction. Clinical implications of these findings are also discussed.