Introduction and goal: Foster care for children in the Republic of Croatia is a form of providing social housing services to children, who are provided with daily care and care in this way. Foster parents are often exposed to numerous challenges in their daily work with children who have experienced neglect and abuse and traumatization. It is also an area of care in which private and business activity cannot be clearly separated, because the work of a foster parent includes providing allday care and concern for children. Although foster parents receive compensation from the social welfare system for their work, they are not employees of the social welfare system, but collaborators. The multitude of roles in which foster parents find themselves can lead to a state of professional stress, and then possible burnout, which can further affect their mental health. Therefore, this research aims to examine the predictive role of some sociodemographic characteristics, experience, resilience, social support, stress and professional burnout in relation to the mental health of foster mothers (emotional state, anxiety and depression). It is a research with an exploitative goal. The theoretical origin of the doctoral research is the transaction theory of stress, the model of professional burnout according to C. Maslach, and the concept of social support and psychological resilience. Participants: Before the implementation of the main qualitative research, preliminary research was conducted in which 16 foster mothers from Osijek - Baranja county participated, and which was conducted through two focus groups. 135 foster mothers from five counties of Slavonia and Baranja participated in the main research, namely Osijek - Baranja, Požega - Slavonia, Brod - Posavina, Vukovar - Srijem, Virovitica - Podravina. In the main research, only foster mothers took part, and they perform foster care as traditional or specialized foster care for children. Most of the respondents are between 40 and 60 years old. Instruments: For the purposes of the research, a survey questionnaire was created that consists of several scales that examine the respondents' general sociodemographic data, their experience, psychological resilience, emotional exhaustion, depersonalization and perception of personal achievement, then social support, the presence of sources of stress, specific competencies for foster care and mental health. The measuring instruments used in the research are Questionnaire of sociodemographic characteristics, Experience of foster care, Resilience Evaluation Scale (RES) Meer et al, 2018; Maslach's burnout inventory (Burnout Inventory MBI-HSS; Maslach, Jackson and Leiter, 2001); Multidimensional scale of perceived social support (Zimet, Dahlem, Zimet and Farley, 1988, Multidimensional Scale of Perceived Social Support - MSPSS); Scale of perceived social support (Social Support Scale, adapted from Simons, 1996); Questionnaire on sources of stress for foster parents; Questionnaire of self-assessment of specific competencies of foster carers; Well-Being Scale (WHO Well-Being Index, WHO, 1998); PHQ4 scale (Patient Health Questionnaire-4, Kroenke et al., 2009). Results: The results in the qualitative part of the research showed that the foster mothers of children in the two focus groups stated how they understood the items listed in the newly constructed instruments, the Questionnaire on sources of stress of foster parents for children and the Questionnaire of self-assessment of children's specific competencies. In addition, the foster mothers who participated in the focus groups state that they want to acquire additional knowledge and skills in the area of child care, child development, educational procedures, cooperation with experts in the system, knowledge of how to deal with stressful situations, and computer skills. Regarding the present sources of stress, they are most often associated with the characteristics of the foster child, then with the lack of support from the social worker and the social care system and the characteristics and difficulties of the foster parent. The analysis of the data also showed how the foster mothers in this research estimate their specific competencies for fostering as high, with the highest results on the items related to the competencies for effectively managing foster care focused on the child and managing the child's behaviour. Also, the results showed that foster mothers mostly do not have pronounced symptoms of anxiety and depression, and only 23,7% of foster mothers have mild symptoms, while 4,4% have moderate symptoms of anxiety and depression. The predictors of the set that include the variables the number of people who actively participate in the care of a foster child, the experience of fostering a child with externalized behaviour problems, self-assessment of specific competencies, social support of social workers in the work environment explain 24% of the variance of the professional source of stress criteria. The predictors of the experience of fostering a child with externalizing behaviour problems, family social support and the presence of a stress source explain 27% of the variance of the emotional exhaustion criterion, while the set of variables of the experience of fostering a child with externalizing behaviour problems, perceived social support from friends and the presence of a stress source explain 15% of the depersonalization criterion. A set of variables, the way of living, psychological resilience and self-assessment of specific competencies explain 18% of the variance of the criterion of perception of personal achievement. The predictors of mental health in this research are the level of education and psychological resilience in relation to the emotional state of foster mothers; the number of people other than foster children cared for by foster mothers, the experience of fostering a child with internalized behavioural problems, the experience of fostering babies and the perceived social support of the family in relation to anxiety, and the number of people other than foster children cared for by foster mothers and the social support of social workers in relation to depression. Conclusion: Among foster carers for children, there are sources of stress related to their role in providing accommodation services to children, some foster carers experience burnout, and have symptoms of anxiety and depression. The experience of fostering a child that shows externalized behaviour problems is a significant predictor of professional stress, emotional exhaustion and depersonalization in foster mothers. A common predictor of anxiety and depression is a greater number of people that foster mothers take care of, in addition to the foster child. Lower support from social workers is a predictor of stress and depression in foster mothers, while the absence of social support from the family is a predictor of emotional exhaustion. The presence of a source of stress proved to be a significant predictor of emotional exhaustion and depersonalization, which confirmed the theoretical origin of the draft research model. All of the above indicates that foster mothers have the right to mental health protection within the social care system because they experience stress related to their role as foster parents. There is therefore a need to provide foster mothers with continuous support and supervision to which they have a legal right. It would also be important for social workers to give them all the necessary information about the child being adopted, as well as to support the foster mothers in the process of working with the adopted child, especially when the child has internalized and externalized problems in behaviour