The Vocabulary Development Project (VDP) was a pilot study designed to demonstrate that significant improvement in language skills is possible with a sustained, massive program of vocabulary exercises. The subjects were inner-city fourth, fifth, and sixth graders. As this project was not a full-blown experimental study, a control group-experimental group paradigm was not used. Tests used were the Gates-MacGinitie (reading comprehension and vocabulary) Test, Iowa Tests of Basic Skills (spelling) and the Lorge-Thorndike IQ Test. Ninety "Pre-tests", ninety "Re-tests" and ten "Mastery tests" developed for the VDP teaching packages also yielded data for each child. Analysis of data showed considerable gains in achievement; the average gain in IQ measures was some four or five points. Samples of VDP tests, and graphs of VDP and standardized achievement test results for sex, IQ, grade, and race analyses are appended. [Part of the Vocabulary Mastery Test in Appendix A will not be clear in hard copy reproduction.] (KG)