This paper presents a structural model of the determinants of harsh parenting among Mexican mothers. One hundred five mothers (46 from the community; 59 referred to agencies for child maltreatment) were recruited from Sonora (Northern) Mexico and interviewed. In this model the use of physical punishment was explained by (1) authoritarian parenting style (mothers' beliefs concerning the effective use of physical punishment and mothers' lack of disciplinary skills) and (2) family dysfunction (a latent variable constructed from reports of interspousal violence and the parents' use of alcohol and drugs). In addition, the indirect effects of demographic and historical variables on harsh parenting was included. The findings show that the most important factor influencing the use of physical punishment in these families was authoritarian parenting style, exerting a significant direct effect on the mothers' reports of their use of harsh punishment. Family dysfunction had an indirect effect through parenting style. Some sociodemographic variables also indirectly influenced the use of beliefs maternal punishment It is concluded that cultural beliefs play a major role in parenting within the framework of Mexican family relations.