The aim of this study was to determine the serum immunoglobulin concentration in both manic patients and in healthy volunteers. The study was conducted with 30 manic patients (24 males and 6 females, aged 55.4 ± 13.0 years); age and gender-matched, control subjects were enrolled. An enzyme-linked immunosorbent assay (ELISA) was employed to analyze the serum immunoglobulin concentrations. IgG level was found to be 18.22±6.42 g/L in the manic patients, while it was 16.05 ± 3.45 g/l in the cohort controls (p=0.487). IgM and IgA concentrations were 6.025 ± 1.07 g/l and 1.41 ± 0.51 g/l in the manic patients, whereas those were 5.73 ± 1.63 g/l (p=0.688) and 0.837 ± 0.36 g/l (p=0.034) respectively in controls. From the results it was found that only the serum concentration of IgA was increased significantly (p=0.034) in manic patients while the concentrations of IgG and IgM remained unchanged. In many psychiatric disorders, immunoglobulin level has been found to be changed significantly. This study reveals that the concentration of IgA in manic patients increased significantly (p=0.034) which usually happens in case of many psychiatric patients. Further studies are suggested with larger population to find out the correlation between immunoglobulin level and degree of disorder and possibility of using as a diagnostic tool for the identification of this disease. Key words: Immunoglobulin, manic, psychiatry. Dhaka Univ. J. Pharm. Sci. Vol.4(2) 2005 The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website