Segmented-in-series solid oxide fuel cells (SIS-SOFCs) were prepared on flattened-tube partially stabilized zirconia supports. The distinguishing characteristic of these cells was the short repeat period, 2.4 mm, and small active cell length, 1.3 min, compared to approximate to 10 mm in previous SISSOFCs. The support tubes, formed by gelcasting, were bisque fired and then screen printing was used to sequentially deposit Ni-YSZ anodes, YSZ electrolytes, and Pt-YSZ composite interconnects. After high-temperature co-firing, LSM-YSZ and LSM cathode layers were screen printed and fired. Each flattened tube side had 12-16 individual cells. For testing, the open tube ends were sealed and humidified hydrogen flowed inside of the tubes; air was flowed over the outside of the tubes. Maximum total power at 800 degrees C was approximate to 8 W and maximum power density was approximate to 0.7 W cm(-2), calculated using cell active area. Good stability was observed during a approximate to 650 h steady-state test. Excellent stability was also observed over 20 redox cycles. (c) 2006 Elsevier B.V. All rights reserved.