Psoriasis is a most prevalent hyperprolifetive skin disorder affecting about 2-4% of the population world wide. Contributing factors for development of different types of psoriasis are genetic, environmental and immunological factors. Diseases characterised by hyperproliferative disorders are mostly associated with the aminoacidopathies due to mutation or presence of polymorphically distributed gene of the metabolic pathway affecting the metabolism. Diseases treated with Antihistaminic, anti proliferative or anti mitotic agents and antihypertensives may develop aminoacidopathy particularly homocysteinemia or homocysteinuria. Cancer and psoriasis vulgaris are also associated with increased homocysteine concentration in plasma. Recently association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphism and psoriasis vulgaris has attracted great interest amongst researchers worldwide. We are therefore interested to find out the correlation with aminoacidopathies (if any) with plaque psoriasis, particularly, methionine, cysteine and homocysteine balance. 34 plaque psoriasis patients and 30 age matched control were chosen from tertiary referral unit of dermatological clinic of Calcutta Medical college Hospital and subjected to amino acid profiling in deproteinized plasma and urine samples. HPLC analysis revealed a significantly increased amount of homocysteine in both plasma and urine compartment of the body of plaque psoriasis patients in comparison to control