Introduction: Mothers differ greatly in their psychological adjustment to parenting, with some mothers being more stressed than others. This study aimed to investigate the role of family life stressors related to the relationship with children and spouse, and the motivation to have children in predicting parenting stress for mothers. The project is based on the parental stress theory and the SDT self-determination theory. We examined whether motivation to have children plays a mediating role in the relationship between family stressors and mothers’ parental stress. Method: Parental stress was measured using The Parental Stress Scale (Berry & Jones, 1995). Motivation to have a child was measured using the Motivation to Have a Child Scale (MCS) (Brenning, Soenens, & Vansteenkiste, 2015). The intensity of difficult experiences in the relationship with the child and with the spouse (family stressors) was assessed using the Family Stressors Scale. The study involved 99 mothers who are in a relationship and have at least one child up to 7 years of age. The families of the surveyed mothers had from one to seven children. Statistical analyzes were performed using SEM structural equation modeling. Results: It was found that difficult situations in relationships with children and spouse increase mothers' parental stress. Intrinsic motivation and amotivation mediate the effect that difficult situations in family relationships have on parental stress. Difficult situations in family relationships are negatively related to intrinsic motivation and positively related to amotivation. Intrinsic motivation to have a child is negatively related to parental stress, while amotivation is positively related to parental stress. There was no relationship between external, identified and introjected motivation, neither with parental stress nor with difficult situations in family relationships (family stressors). Conclusions: In confrontation with stressors, the intrinsic motivation to have a child plays a protective role against experiencing parental stress by mothers, while amotivation intensifies this stress. The implications of the results for future research and clinical interventions are discussedThe implications of the results for future research and clinical interventions are discussed