This study will examine the efficacy of an in-home training program designed to promote positive father-child relationships in preschool children diagnosed with Attention Deficit Hyperactivity Disorder (ADHD). Six fathers with ADHD children ages 3-6 years, will be taught father training skills during three in-home training sessions over a 12 week period. The in-home training will incorporate positive approaches utilizing Cognitive Behavior Play Therapy (CBPT) as follows: (a) setting up positive and functional child play sessions/how to follow the child's lead in play; (b) using praise and rewards effectively/avoiding negativism; and (c) using strategies for setting and enforcing limits in maladaptive behavior. The fathers will conduct play sessions in their homes with their children five times per week for 12 weeks. Two instruments will be used to described subjects: (a) The Eyberg Child Behavior Inventory (ECBI) as criteria for inclusion; and (b) The Hollingshead Four Factor. Dependent variables will be measured by: (a) The Child Behavior Checklist (CBCL); and (b) Direct Observation of Father and Child Behaviors (D0FCB). An adapted version of the Therapy Attitude Inventory (TAI) will assess parental satisfaction and a semi- structured interview will provide information regarding parental perceptions of the training process. A single subject, AB experimental research design will be used to assess father acquisition of child-training skills. Child behavioral responses, and father-child reciprocity will also be monitored. This will provide essential information regarding interactions of fathers & their ADHD children as well as specific components of an in-home training package. This information is critical for further work with fathers of ADHD children about which little is currently known.