Acceptor-doped cerium pyrophosphates have shown significant proton conductivity of >10-2 S cm-1 in the range of 100 - 300oCand are considered promising candidates for use as electrolytes in proton-conducting, ceramic electrolyte fuel cells (PCFCs). But,cerium pyrophosphates themselves do not have structural protons, and protons incorporate into their material bulk only as impuritieson exposure to a hydrogen-containing atmosphere. However, proton incorporation and proton conduction in these materialsare expected to be affected by factors such as the nature (ionic size and charge) and concentration of the aliovalent dopant, processinghistory (synthesis route and microstructure), and the presence of residual phosphorous phosphate (PmOn) phases. An exactunderstanding of these aspects has not yet been achieved, leading to large differences in the magnitude of proton conductivity ofcerium pyrophosphates reported in various studies. Herein, we systematically address some of these aspects, and present anoverview of factors affecting proton conductivity inacceptor-doped CeP2O7.