Chronic pain represents a wide-spread and costly problem that is often not treated effectively with traditional biomedical approaches (Turk et al., 2011). The literature emphasizes the importance of using psychological interventions that encourage self-management of pain. This study tested the effectiveness of two brief, online writing interventions that can be used by chronic pain patients in a wide-spread and cost-effective way (Kerns et al., 2001). Writing interventions have been found to produce beneficial psychological and physical outcomes for those with pain (e.g., Frattaroli, 2006,). This study added to the literature by using positive variations of the expressive writing paradigm that focused on self-compassion and self-efficacy, and testing the moderator variable of pain catastrophizing. Ninety-three participants with chronic pain were recruited from chronic pain forums and completed the writing intervention. Participants were randomized to either self-compassion or self-efficacy writing and wrote for 20 minutes once a week for three consecutive weeks. Participants completed baseline and post-intervention measures of pain severity, illness intrusiveness, pain acceptance, pain catastrophizing, depression symptoms, life satisfaction, self-compassion, and chronic pain self-efficacy. Results indicate that participants in both writing conditions reported significantly less pain, less depression, and greater self-compassion after the writing. Moreover, participants reported feeling more positive after each writing session. One significant difference emerged between the two types of writing: participants in the self-compassion condition reported less intrusive pain, whereas those in the self-efficacy condition reported more intrusive pain after the writing. In conclusion, although both types of writing have beneficial effects on psychological and physical health for those with chronic pain, the self-compassion writing may be even more favorable than the self-efficacy writing.