Streptococcus pneumoniae (pneumococcus) is the most frequent causative agent of acute bacterial pneumonia. Outstanding characteristic of pneumococcus is an ample polysaccharide capsule that is highly anti-genic agent and is the major factor for classification of pneumococcus into more than 94 serotypes. In this study, production of capsular polysaccharide from Streptococcus pneumoniae type 23 was optimized by supplementation of metal ions or by modulation of culture conditions. When brain heart infusion (BHI) broth was supplemented with 1 mM concentration of $CaCl_2$, $CuSO_4$ and $MgSO_4$, growth of pneumococcus as well as polysaccharide yield were stimulated. Also slight aeration gave rise to better polysaccharide yield.