Abstract: This research aimed at identifying the effectiveness of a program based on differential reinforcement in developing the personal safety and security skills of autistic children. The sample consisted of (5) children with an autism spectrum disorder in early childhood enrolled in Basmat Amal Center in Mallawi, Minia Governorate. The sample comprised one experimental group that was homogenous in terms of intelligence and chronological age (3: 6) years. The scale for diagnosing some self-care skills of the autistic child (prepared by the researcher), the Childhood Autism Rating Scale (C.A.R.S), The Stanford Binet Intelligence Scale (5th ed.) (by Mohamed Taha Mohamed, Abdul Mawgoud Abdul Sami, Mahmoud El Sayed Abu El Nil 2011), and a program on differential reinforcement in developing personal safety and security skills for autistic children in early childhood (prepared by the researcher) were applied on the study sample. The program consisted of some activities for developing personal safety and security skills. The program was implemented over 3 sessions per week for a period of two and a half months. Results revealed that there were statistically significant differences between the pre-and post-measurements means ranks of degrees of the group under study on the self-care scale for autistic children in favor of the post-measurement, which proved the effectiveness of the program in developing some personal safety and security skills for autistic children. Besides, there were no statistically significant differences between the post- and follow-up measurements, which indicated the continuity of the program effectiveness. The research concluded with some research suggestions and recommendations.