Writing an integrated essay based on multiple-documents requires students to both comprehend the documents and integrate the documents into a coherent essay. In the current study, we examined the effects of summarization as a potential reading strategy to enhance participants’ multiple-document comprehension and integrated essay writing. Participants (n = 295) were randomly assigned to either summarize or reread five texts on sun exposure and radiation. They produced an integrated essay based on the texts that they read, which were scored by expert raters. Finally, the participants completed three knowledge assessments (topic, domain, general). Readers who summarized texts had lower essay scores than readers who reread the texts. However, within the summary group, summary quality was positively correlated with essay score. These findings are discussed within the context of multiple-document comprehension and writing skill.