The relationship between level of cognitive functioning at the beginning of first grade and level of reading achievement at the end of first grade was investigated in a sample of 325 children. The EITS Concept Assessment Kit-Conservation was used to classify the children as being in the preconceptual stage, the intuitive stage, or the concrete operational stage. Achievement at the end of first grade was assessed with the Stanford Achievement Test-Reading Tests. Analysis of results indicated a significant main effect for cognitive level for vocabulary and for word reading and a significant sex-by-level interaction for reading comprehension. There were significant differences in achievement, favoring the girls in the sample, for word reading, reading comprehension, word study skills, and total reading. (Author/AA)