The aim of this study is to maintain the constant frequency in the utility using constant frequency unified power quality conditioner with fuzzy logic controller. A Constant Frequency Unified Power Quality Conditioning system (CF-UPQC) consists of a Unified Power Quality Conditioner (UPQC) and a matrix converter based frequency changer. UPQC is a combination of series active and shunt active filter. The series active filter and shunt active filters are used to compensate the voltage, current imbalance and harmonics. Frequency converter (matrix converter) is used to regulate the supply frequency when it varies beyond the power quality limit. The performance of the CF-UPQC is compared with fuzzy controller against conventional controller.