This research aims to examine the effectiveness of two different vocabulary learning strategies on vocabulary retention. The first is learning words in isolation in which learners learn new words and their meanings presented in the form of word lists; and the second is learning words from context in which learners use clues in sentences in texts to generate meanings for the target words. In the instruction sessions, a group of senior high school students learning vocabulary in isolation was presented with a number of words in English and their meanings. Their task was to say and repeat the words and their meanings several times as they attempted to learn the new words and their meanings. The group of students learning words from context was presented with some texts containing the target words and was asked to find out the meanings of the target words by using clues in the texts. Recall tests were administered twice, a week and two weeks after the instruction sessions. For word retention, results of the recall tests revealed that learning words in isolation appeared to be more effective than learning words from context. Students learning words in isolation retained the target words and the meanings better than those in the other group.Keywords: Word Lists, Context, Vocabulary, Retention