This study assesses information processing and memory functioning in 50 children diagnosed with Attention Deficit Hyperactive Disorder (ADHD) with and without learning disabilities (LD). Mode of presentation (visual vs. auditory), type of memory processing (immediate, short-term, and long-term), and order of recall (ordered vs. unordered) were assessed using the Learning Efficiency Test-II (LET-II). Both groups demonstrated difficulty with auditory ordered recall and lost substantial information from immediate memory to short-term and long-term memory stores. The ADHD/LD group also demonstrated more difficulty with ordered recall than the ADHD only group. While there were no differences between the two groups in regard to immediate recall, the ADHD/LD group demonstrated more problems transferring information into short-term and long-term memory stores than the ADHD only group. Verbal interference effects significantly decreased retention for both visual and auditory processing. Results indicate that ADHD alone presents significant problems in information processing, but the comorbid effects of a learning disability further intensify the negative impact of ADHD. © 1996 John Wiley & Sons, Inc.