Data on the association between fibromyalgia syndrome (FMS) and psoriasis are scarce. We aimed to examine the association between FMS and psoriasis using a large-scale observational population-based study. This cross-sectional study analyzed data from a big computerized database to evaluate potential differences in the prevalence of psoriasis between patients with FMS and matched control subjects. The study included 18,598 patients with FMS and 36,985 controls. The prevalence of psoriasis was increased in patients with FMS as compared with control subjects (6.7% vs. 4.8%, respectively; OR, 1.4; 95% CI, 1.3–1.5; P < 0.001). This association was robust to multivariate analysis adjustment for sex, age, ancestry, socioeconomic status, and healthcare utilization (OR, 1.3; 95% CI, 1.2–1.4; P < 0.001). When compared with patients with only FMS, patients with a dual diagnosis of FMS and psoriasis presented with FMS at a significantly older age, had a higher mean BMI, and a higher frequency of smoking. To conclude, we found a significant association between FMS and psoriasis. More extensive cooperation between dermatologists and rheumatologists is suggested to enable early identification of their co-occurrence.