Assignment of underlying cause of death (UCOD) might be inconsistent among coders if physicians do not properly record cause of death on death certificates. This study aimed to assess the changes in the quality of tuberculosis-related UCOD assignment in Taiwan after interventions by the Center for Disease Control (CDC). Methods: The reference (gold standard) we used to assess the quality of UCOD assignment by coders was the UCOD selected by the Automated Classification of Medical Entities (ACME) computer program. The agreement, overand under-coding rates between coders and the reference were calculated by years before and after the CDC interventions. Results: An abrupt decrease in tuberculosis death rates according to the UCOD assigned by coders was noted from 2003 to 2004, but no such decrease was noted according to the reference. The agreement in UCOD assignments between coders and ACME decreased from 0.75 in 2001 to 0.67 in 2005. We found a significant decrease in the over-coding rate from 0.21 in 2003 to 0.11 in 2004, and a prominent increase in under-coding rates from 0.08 in 2003 to 0.24 in 2004. Conclusion: The abrupt decrease in the official published tuberculosis mortality rate from 2003 to 2004 was due to significant changes in the practice of UCOD assignment of official coders, which might have been a response to interventions initiated by the CDC.