There have been major influential views on the learning of L2 vocabulary through reading. One approach promotes explicit vocabulary learning through vocabulary activities. However, it is not clear whether there is an effect of text comprehension on vocabulary learning when reading and doing exercises for vocabulary learning. The present study was designed to investigate the relationship between text comprehension and learning vocabulary through word-focused activities. The participants were 100 first year students. They were given a vocabulary checklist before the treatments to make it sure that all participants were unfamiliar with the target words. There were four groups and all groups read one text each week during eight weeks. Each text contained one target word which appeared six times in the text. The treatment group read the texts, answered the comprehension questions and they completed the vocabulary activities. Then, they answered the form-recognition and meaning recognition tests as the last step of the process. On the ninth week, and tenth week, the participants were given the delayed post-tests to investigate whether they are familiar with the target words after treatments. First, participants’ answers to comprehension questions were analyzed. Then, means were calculated for form– recognition and meaning-recognition tests. Comprehension and vocabulary learning were compared for treatment and control groups. The analyses showed that the treatments have an effect on learner scores and results when learning an unknown word. One of the aims of the study was to explore the effect of completing a variety of vocabulary exercises while reading. It seemed to have tapped different levels of processing capabilities such as recognition and interpretation. The analysis showed that there is not a significant correlation between vocabulary learning through word-focused activities and text comprehension. It is concluded that to learn vocabulary through reading, text comprehension is a necessary condition.