The aim of this study is to examine the changes in computer attitudes and self-efficacy of biology students after a formal computer course. 22 students are chosen from Hacettepe University, Department of Biology Education in 2004-2005 education year. In this experimental study, one group, pre-test, post-test model has been applied. Before the study, computer achievement test with a .78 reliability coefficiency, a self-efficacy scale regarding computers with a .71 reliability coefficiency, and an attitude scale with a .90 reliability coefficiency had been applied as pre-tests. After a 10-week computer course, the same scales had been applied as post-tests. Wilcoxon test had been used in order to check if there is a difference between the test results applied before and after the course. According to the results of the study, the computer course was efective and had a significant influence on the computer self-efficiency of students. However, it did not have a significant influence on the development of a positive attitude.