This paper presents the operating results of micro tubular solid oxide fuel cells (MT-SOFCs) integrated with propane catalytic partial oxidation (CPOX) reformers. The cells combined with the propane CPOX reformers successfully survived 1000 continuous thermal cycles totaling 1922 h of operation with only a 0.47 mW power loss per cycle, as well as surviving 100 extreme thermal cycles with a maximum ramp rate of 1000 degrees C.min(-1) without any power loss. This excellent thermal shock resistance is due to both the well matched coefficient of thermal expansion (CTE) among all of the cells' layers as well as the homogenous anode structure present in all of the cells. Additionally, the cells operated on propane for more than 1500 continuous hours with an average degradation rate of 0.067 mW h(-1) (0.58%/1000 h). This degradation was attributed to the sintering of the nickel in the anode, degradation of the current collection and the reformer. The fact that the cells showed no sign of delamination, cracking or coking after these tests also proves the successful integration of cell and CPOX reformer. Overall, the 3D printed MT-SOFCs with integrated CPOX reformers exhibited a breakthrough in terms of cell thermal cycling and long-term stability which will significantly advance the development of portable SOFCs systems. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.