We developed novel Ag-glass composite interconnect materials for anode-supported flat-tubular solid oxide fuel cells (SOFCs) operated at 700 degrees C by optimization of the glass content. For this purpose, the variations of phase stability, area specific resistance (ASR), microstructure, gas leak rate, cell performance, and open circuit voltage (OCV) were determined for the Ag-glass composite materials with respect to the glass content. The Ag-glass composite materials maintain phase stability without chemical reactions. The ASR increased as the glass content increases due to glass existing as an insulator between the Ag phases. All the composite materials showed dense coating layers on the anode support and had a low gas leak. The cell performance and OCV were measured to identify the optimum composition of the Ag-glass composites. Our results confirm that Ag-glass composites are suitable for high performance interconnects in anode-supported flat-tubular fuel cells operated below 700 degrees C.