Knowledge of illness perception may aid the identification of groups of patients with a higher risk of coping poorly with the demands of their illness. This study aims to investigate associations between illness perception, clinical characteristics, patient knowledge, quality of life and subjective health in persons with psoriasis. The present study was based on cross-sectional data from patients awaiting climate therapy in Gran Canaria. We included 254 eligible patients (74%) who completed a questionnaire including the revised Illness Perception Questionnaire, the Psoriasis Knowledge Questionnaire, and the Dermatological Life Quality Index. Disease severity was measured using the Psoriasis Area and Severity Index. Several statistically significant associations between clinical characteristics, knowledge and various illness perception dimensions were found. Illness perception was also significantly related to disease-specific quality of life and subjective health. These findings contradict previous findings, which suggested that objective disease factors are not relevant to illness perception in psoriasis.