Preschool education is the first formal education process that supports the physical, affective, psychomotor, self-care and cognitive development of children. Children's participation in preschool education should be supported, as pre-school education provides children with the opportunity to learn during this critical period of the rapid development of children. Pre-school education is prepared in line with the needs of all children, including children with special needs, by providing equal opportunities in education and preparing them for primary school. Children with special needs should be encouraged to be involved in the pre-school education process through inclusive education. The aim of this research is to develop a pilot in-service training program for inclusive practices by taking the opinions and suggestions of pre-school teachers and examine the effect of the program on teachers' efficacy and attitudes towards inclusive education. 15 pre-school teachers participated in the study on a voluntary basis. A mixed-method with the exploratory sequential design was used in the research. The research data were collected with the needs analysis form, the information form, the teacher efficacy for inclusion scale, the attitude scale for inclusion, the open-ended questions form and the focus group interview form. The quantitative data were analyzed by arithmetic mean and paired t-test. The answers to the open-ended questions were presented with content analysis and the responses obtained from the focus group interview were given as they were in order to exactly reflect the views of the teachers in the qualitative data. In conclusion, in-service training has provided an increase in the arithmetic mean of efficacy and attitude of teachers. Moreover, the teachers participating in the training expressed their positive opinions. Though teachers generally feel competent in inclusive education, they stated that they need training for inclusive education. It was concluded that support education services, classroom size, training for teachers and cooperation with other people involved in inclusive education are effective in the teacher's attitude.