Little is known about how patient functioning changes after completion of multidisciplinary pain programs, and what factors are associated with such changes when they occur; for example, whether improvement or deterioration in functioning corresponds to changes in patient beliefs and coping during this period. The objective of this study was to examine the extent to which changes in patient pain and functioning were associated with changes in beliefs and coping after multidisciplinary pain treatment. Patients with chronic pain (N = 141) completed outcome (pain, functioning) and process (beliefs, catastrophizing, coping) measures at the end of multidisciplinary pain treatment and 12 months posttreatment. On average, patients reported similar levels of pain at both times, but showed a small worsening in disability and depression outcomes between posttreatment and follow-up, which were associated significantly with concurrent changes in the process measures. In particular, increased belief in oneself as disabled by pain, catastrophizing, and increased use of resting, guarding and asking for assistance in response to pain were linked with increased disability and depression. Decreased perceived control over pain was also consistently associated with worsening of these outcomes. The results highlight the potential importance of specific pain-related beliefs and coping responses in long-term patient pain and adjustment. Research is needed to determine whether booster interventions after the end of intensive multidisciplinary treatment that target these beliefs and coping responses improve long-term outcomes.