The effects of certain factors on the continuous production of NADP(+) with immobilized NAD(+) kinase were studied. In a column reactor the maximum NADP(+) productivity was experienced at pH 8.0. The presence of 10-12 mM Mg2+ ion appeared to be optimum for maximum productivity. K+ ion at 1-5 mM behaved as an activator. Mn2+ and Zn2+ ions proved effective activators of the immobilized NAD(+) kinase. Systems of up to three or four columns were most effective in NADP(+) production.