Increasingly, states are legalizing cannabis for recreational use. Improved accessibility may allow adults with pain to use cannabis more liberally. Greater understanding is needed about how adults with pain perceive the effects of cannabis, particularly those who also use opioid analgesics. To examine the perceived effects of cannabis among adults who have been prescribed opioids for persistent pain. A survey-based study was conducted on 150 adults with persistent pain. Data from two open-ended questions were analyzed using a qualitative descriptive approach and content analysis. Data analysis led to identification of two main categories and five subcategories: (a) cannabis benefits with two subcategories of "physiological" and "mental health"; (b) adverse effects with three subcategories of "physiological," "mental health," and "social and economic concerns." Both positive and negative effects of cannabis were described. Nursing practice, including open communication with patients, can be guided by patient perspectives surrounding benefits and adverse effects of cannabis use. Copyright © 2018 Elsevier Inc. All rights reserved.