As the use of e-fi ling of tax returnshas spread from developed to developingcountries,it has been clear that this sort of reform can reduce errorsand opportunities for corruption. Also, it has been widelyassumed that taxpayercompliance costs woulddecrease with the use of e-fi ling, because less timeisspent getting tax returns from the taxpayer tothe revenue authority. This notesummarizesfindings from tax compliance cost surveys and offers acautiouslypositive assessment of e-fi ling reformsin developing countries with a numberof caveats.Countries should not rush to push e-fi ling on all taxpayersuntilthe revenue authorities, infrastructure, andtaxpayers are ready.