Nowadays Information and Communications Technology (ICT) is becoming not only enormously popular but also increasingly important in our lives and education system. Generally, learners are usually eager to work on computers or with various kinds of modern technology. This research was carried out to find out whether using weblogs is effective in Iranian EFL learners’ vocabulary and writing skills. To do so, two samples of learners were selected through an OPT test as the control and experimental groups, and a pretest of vocabulary was administrated. Then, the traditional methods of teaching vocabulary and writing were used for the control group, and weblogs were used for the experimental group. After three months of instruction, another test of vocabulary and writing was given as the posttest to the students of both groups to assess their achievement. The results of the analysis of ANCOVA showed that weblogs were more effective than the traditional ways of teaching vocabulary and writing