According to the data of HZZO (Croatian Institute for Health Insurance), there are 32,101 children with disabilities and major developmental difficulties living in the Republic of Croatia. Children with developmental disabilities and their families are included in early intervention and rehabilitation programs during the continuous rehabilitation process with the aim of maximizing the child's abilities, the best possible inclusion of the child and the most effective support of the family. One ofmany rehabilitation programs includes the coexistence of an service dog/guide dog in the family of a child with developmental disabilities. After the learning process, with the help of work instructors, the service dog/guide dog becomes the parent's personal assistant and rehabilitator in the home of the child withdevelopmental difficulties. Available research points to the high benefits of including a service dog/guide dog in the life of the family of a child with developmental disabilities, both for the child and for the family. Service dogs/guide dogs enrich the life of a child with disabilities and the whole family and they motivate the child and the family to play an active role in the rehabilitation process and help better interaction with the environment. Since there are only a few available studies on this topic in the Republic of Croatia, this paper aims to examine and assess the connection between the well-being of children with developmental disabilities and their families with a service dog/guide dog. Families of children with developmental disabilities who have a dog participated in the research service dog/guide dog. The data was collected through a survey questionnaire specially created for this research in electronic form using Google Forms with the support of the Silver Rehabilitation Center. We set several hypotheses based on studies of available choices. The first hypothesis states that there is no difference in well-being in relation to sociodemographic variables: the age of the child with developmental disabilities, age, level of education, gender of parents and place of residence. The age of a child with developmental disabilities, the age, level of education and gender of the parents do not affect the assessment benefits. The difference was observed in the families of respondents who live in urban areas and families of respondents living in the countryside, where a statistically significant association of well-being with life in the city. Children with disabilities and families who had pets even before getting a service dog/guide dog estimate greater improvement in motor, social and emotional expression after getting a dog from those who previously did not have pets, as a hypothesis is not proven. Family members estimate that emotional, social and motor wellbeing expression exists and is equal regardless of previous ownership of a pet. The third hypothesis is that families of children with multiple developmental disabilities (2 or more disabilities) estimate greater wellbeing in terms of motor, social and emotional expression with the dog of a service dog/guide dog than families of children with one developmental disability and this has not been proven. Greater well-being is expressed by family members whose children have only one developmental disability. The fourth hypothesis stated that society's misunderstanding of the service dog/dog the guide does not diminish the benefits to the child and the family of the child with developmental disabilities daily activities and skills, with which the parents agreed and confirmed the fourth hypothesis. Given that the parents expressed the benefits of living together with a service dog/guide dog in areas of motor, social and emotional expression and positive changes in the environment, it is important to work on promoting positive attitudes towards service dogs/dog guides in the rehabilitation of children with developmental disabilities in the household. Occasional protests from the environment did not diminish the value of wellbeing, but they pointed to a lack of recognition of the role and benefits of a service dog/guide dog from the environment: public transport, shops, education system, tourist accommodation, public areas where sometimes ignores the fact that the dog is a service dog and support, an assistant and a friend. For the future, our task is to promote positive attitudes in society and the environment towards dog service dogs in the rehabilitation of children with developmental disabilities.