How similar are the cognitive and linguistic profiles of those children who easily learn to read? How similar are the profiles of those children who have difficulty learning to read? Do the profiles of successful and less successful readers vary among children 5–10 years of age? These were the questions that guided this study. Six core profiles were identified on four fluid reasoning to comprehension knowledge constructs previously found to be both theoretically and empirically linked to children's reading acquisition: auditory processing, crystallized ability, processing speed, and short-term memory. Cluster analysis was used to develop this taxonomy and the six-cluster solution was supported through cross-validation. The internal and external validity of the resulting profiles was favorable, suggesting homogeneous within-cluster membership and clear separation among the six core profiles. A summary of the defining characteristics for each profile is provided. The performance of children comprising different profiles was investigated on four external reading outcomes. These comparisons were conducted for each of the six age groups comprising the sample (i.e., 5–10 years) to assess whether the importance of certain score configurations varied as a function of the reading tasks required of children learning to read and those who are already readers. Results indicated that certain profiles were associated with greater success on external measures of reading achievement than other profiles. Trends across ages and differences among age groups are described.