Several investigators have discussed the need to distinguish between the common versus unique dimensions of attention, memory and executive function abilities (Lyon, 1996; Morris, 1996). For example, Mirsky's four factor model of attention contains shift, encode, sustain, and focus/execute dimensions (Mirsky, 1996). However, skills such as flexibility, vigilance, response inhibition, and directed attention have also been considered dimensions of executive function. In a recent factor analysis of memory measures in a child and adolescent sample, Sillanpaa and DeLuca (1995) reported a three-factor solution that included dimensions of attention, explicit and implicit memory. The attention factor was similar to the encode dimension identified by Mirsky. Clearly, common factors have emerged even in the separate analyses of the dimensionality of attention, memory, and executive function skills. However, there has been no attempt to date investigating the combined factor structure of attention, memory, and executive function skills. The purpose of this project is to test uni- and multi-dimensional models of these abilities using confirmatory factor analysis. A total of 160 children and adolescents referred to an outpatient clinic because of suspected learning and behavior problems were employed. All subjects were between 9 and 14 years of age and evidenced a Wechsler Full Scale IQ between 80 and 120. Fourteen variables were subjected to confirmatory factor analysis using Lisrel 8.0 for Windows. Competing a priori models of one to five factors were tested. A five-factor solution represented the best fit of the data using multiple criterion. The resulting factors were as follows: Attention (Encode), Incidental or Implicit Memory, Explicit Memory, Cognitive Flexibility (Shift), and Task Adherence (Focus/Execute). Measures of response inhibition and planning were not available for analysis. Inclusion of the latter would likely result in additional factors.