Mindfulness is a special type of attention, namely focusing on the current moment in a non-judgmental manner. Extensive mindfulness-based interventions have been shown to have positive effects in patients with psoriasis. However, it is unclear whether brief (2-week) interventions are also beneficial. Therefore, the aim of this study was to investigate the effects of a 2-week mindfulness-based intervention in patients with psoriasis. Patients were randomly assigned to an experimental (treatment-as-usual + mindfulness-based intervention) or control group (treatment-as-usual) during their clinic stay. All variables were measured by self-report using validated questionnaires: primary outcomes were mindfulness and self-compassion, secondary outcomes were itch catastrophizing, social anxiety, stress and skin status. Variables were assessed prior to, immediately and 3 months after the intervention. Effects were tested by repeated-measures analysis of variance (ANOVA). Analyses of pre-post-measurements (n = 39) revealed a significant interaction effect on self-reported mindfulness [F(1,35) = 7.46, p = 0.010, η2p = 0.18] and a tendency to a significant effect on self-reported self-compassion [F(1,36) = 3.03, p = 0.090, η2p = 0.08]. There were no other significant effects, but most descriptive data were in favour of the experimental group. However, the control group showed a greater improvement in skin status. Further studies are needed to replicate these findings and investigate which subgroups especially profit from such an intervention.