More sophisticated graphing calculators available for college students can be incorporated into college algebra classes to result a higher student achievement. For this purpose, in this study 117 college students were randomly assigned into either experimental groups where students were allowed to the use of graphing calculators or control groups where the traditional lecture format was given. Pre-and-post measurements were made on students' algebra knowledge in two levels: action and process levels. Action questions were routine, basic, and conceptual questions, whereas process questions were high level, procedural questions. Result indicated that regardless of initial differences, the average and process pre- to post-treatment gain of students in the experimental group was significantly higher than in the control group. There was no significant difference detected between the groups in terms of action gain. Suggestions for future research were discussed. (Contains 5 tables.)