The primary purpose of this study is to find out which approach is more effective, text-based approach or dictionary-based approach, in learners’ mastery of new words and the time duration in learners’ memory. Group A learners received a text containing ten target words with explanations. Group B learners received the material of the same target words with meanings and examples. Ten minutes later, both groups  were given the same test. Two weeks later, all of them took the same test as in the first test.  Learners in Group A showed statistically more significant gains in their vocabulary knowledge in both tests than Group B learners, and they retained the words for longer than Group B. This study thus demonstrates that the text-based approach is more effective than the dictionary-based approach in mastering and memorizing new words.