Laboratory testing and field development have been conducted utilizing a novel organic treatment for closed loop cooling applications. The program is free of both molybdate and nitrite and provides equivalent corrosion and deposit control efficacy relative to current closed loop treatments. The program also utilizes significantly lower overall chemical treatment dosages relative to conventional programs. Laboratory and field trial performance data will be presented. Keywords : closed loop, cooling water, chilled water, mold, mold water, corrosion inhibitor, deposit control, molybdate, nitrite, phosphonate, carboxylic acid