Background: It is largely unknown which unmet needs in the Camberwell Assessment of Need Short Appraisal Schedule (CANSAS) need to be resolved in order to improve a patients' subjective quality of life (QoL). We therefore investigated the pattern of individual unmet needs over time and its relation to QoL over time. Methods: Using data gathered from 251 patients in a Routine Outcome Monitoring procedure in Assertive Community Treatment (ACT) teams, we used paired samples tests to analyze differences in QoL total scores and the number of unmet needs between baseline and follow-up data. Ordinal regression was used to analyze the relationship between outcome in individual unmet needs and QoL. Results: As well as small improvements in QoL over time in patients in contact with ACT, we found a small to moderate decrease in unmet needs over time. While a decreasing number of unmet needs was associated with an increase in QoL, outcomes in QoL and individual unmet needs were weakly related (r <= .165). Ordinal regression analysis showed that a better outcome in individual unmet needs related to accommodation and day-time activities was weakly related to a better outcome in QoL. Conclusions: Patients receiving ACT make small improvements in their QoL and ACT may help to solve some of their needs. QoL benefits from reducing needs for care, in particular the need for appropriate housing and meaningful daytime activities.