Corpus literacy is the ability to use corpora--large, principled databases of spoken and written language--for language analysis and instruction. While linguists have emphasized the importance of corpus training in teacher preparation programs, few studies have investigated the process of initiating teachers into corpus literacy with the result that few guidelines exist for training teachers to make optimal use of corpus output. This study uses a case study approach to examine six pre-service language teachers' development of multiple components of corpus literacy during a semester-long introductory grammar course through which corpus linguistics was threaded. Results showed that while corpus literacy training was generally effective, that effectiveness varied among subjects. Examining the sources of that variation suggests several practices for teacher educators planning or modifying instruction in corpus literacy. (Contains 1 figure.)