The Grid Systems is a phonetic learning device designed by McGinley (1982) to develop adult vocabulary. The name is derived from the fact that the student workbook is set up on a grid, with the top of the page showing the vowel sounds and the left side the consonant sounds. Words are formed on the grid where these sounds combine (some of the spaces on the grid will be empty because that coordinate of sounds does not make a word). First the teacher, then the student says these words, progressing from monosyllabic to multisyllabic words. The repetition allows students to deduce generalized rules for spelling and pronunciation of an ever increasing number of vocabulary words. To determine what effect instruction in the Grid Systems would have on the reading comprehension of college students in developmental reading classes, 141 students in three separate classes received supplemental grid instruction. A control group of 42 students received no such instruction. Pretesting and posttesting were done with a standardized reading comprehension test. Results showed that those students receiving instruction in the Grid Systems showed a significant grade gain in comprehension over those in the control group who did not receive such instruction. (FL)