Background Several recent reports have shown a significant association between psoriasis and metabolic syndrome (MBS). Objective The goal of this study was to investigate the prevalence of MBS and, in particular, the main factors that determine this syndrome in Moroccan patients with psoriasis. Methods A case–control study has included 150 patients with psoriasis and 300 controls matched for age and sex, the MBS was defined according to the International Diabetes Foundation, and the severity of psoriasis was assessed by body surface area. Results Mild psoriasis was seen in 10.7%, 40.3% had moderate psoriasis, and 49% had severe psoriasis. MBS was higher in cases than in controls with statistical differences (44.7 vs. 2.7%, odds ratio OR: 26 CI: 12.4–54.3; P = 0.000). Abdominal obesity and dyslipidemia were the only metabolic factors significantly related to psoriasis whereas diabetes, hypertension, smoking, alcohol consumption, and cardiovascular diseases were not significant. MBS increases with age in our patients with psoriasis, whereas there was no relationship between MBS and gender. Hypertension (P = 0.007), diabetes (P = 0.003), and increased level of triglycerides (P = 0.05) and high‐density lipoprotein cholesterol (P = 0.003) were associated with the severity of psoriasis. Conclusion Metabolic syndrome is an important comorbidity in patients with psoriasis, and vigilance and enhanced screening may be important in this population, especially patients with severe disease.