A labdane diterpene dialdehyde was first time isolated from the chloroform extract of rhizomes of Curcuma amada. This compound exhibited antitubercular activity (MIC=500 microg/mL) against Mycobacterium tuberculosis H(37)Rv strain in BACTEC-460 assay. Two of its semisynthetic analogues also exhibited antitubercular activity at 250-500 microg/mL. It is the first report on isolation and antimycobacterial activity of this dialdehyde from C. amada.