Two approaches to vocabulary instruction, rich instruction and traditional instruction were examined to compare their effectiveness in assisting students in developing word knowledge and transfer of that knowledge to use of target words in expository writing. Fourth grade students in an urban school district were taught twelve Tier Two words over the course of five days using either rich instruction or traditional instruction. Rich instruction consisted of exposing students to both definitional and contextual information, multiple exposures and active or deep processing of each word. Traditional methods included dictionary definitions, matching activities, cloze sentence activities and sentence writing. Outcomes were measured on tasks of word meanings, depth of word knowledge, writing quality and number of target words used in writing. There were no differences between groups on knowledge of word meanings but students who received the rich instruction outperformed students who received the traditional instruction on all other measures suggesting that rich instruction is more effective in helping students to deepen word knowledge and utilize newly learned words in complex literacy acts such as writing. Interpretations and implications are discussed.