Psoriasis, a chronic common immune-mediated disease with frequent remitting/relapsing courses, has a high negative impact on the quality of life, especially in patients moderately or severely affected by the disease. It is also associated with various co-morbidities resulting in a decreased life expectancy and remarkable socioeconomic costs. At least one third of the patients who suffer from it has moderate or severe psoriasis and require continuous treatment to control disease activity. The therapeutic approach in daily practice is usually determined by the severity of the disease. Whether the definition of disease severity is not always clear, there is a considerable number of patients requiring systemic treatment to control the symptoms of psoriasis. The treatment options available for the management of moderate-severe psoriasis have dramatically increased over the past decade, and now range from phototherapy to traditional systemic treatments to biologics. Available data from clinical trials and growing number of patients treated with biologics shows that this new agent are effective and relatively safe to control psoriasis, and are coupled with improved tolerability, convenience and improvement in quality of life. This review shortly presents the characteristics, safety and efficacy profile of the conventional and newer systemic drugs used in moderate-to-severe psoriasis.