Labdanoids are one of the main diterpenoids in the leaf surface resin of Oriental tobacco. They are thought to give a unique taste and aroma to Oriental tobacco leaf. However, there have been no reports referring to the comprehensive quantitative results of the various labdanoids. Identification of the main labdanoids was therefore conducted, and the identified substances were subsequently quantified to compare their compositions among tobacco leaves. The procedure of identification was based on the following: The n-hexane extract from the Oriental tobacco was subjected to silica gel column chromatography for separation, and then each eluate was analysed using a GC/MS. Identification was carried out by comparing the mass spectrum with the previously reported one. This procedure enabled us to identify 15 labdanoids such as cis-abienol, sclareolide, epoxylabdans and levantenolides. Since several authentic standard components for calibration were not available, a GC/FID was selected to use its versatile sensitivity dependent on the molar quantity. The quantities were calculated by comparing them with the peak area of authentic sclareolide. Although the quantitative analysis was based on the procedure of identification, some modifications shown below were introduced; an internal standard (n-heptadecanol), solid phase extraction and appropriate column (DB-35MS) for separation were additionally given to the process. The validation study using sclareolide gave the desirable values as follows: linearity with a correlation coefficient greater than 0.999 (0.5 to 32.0 µg/mL), recovery ratio of 105.6, 101.9 or 103.5% (spiked with 1.02, 4.07 and 16.30 µg/mL of sclareolide, respectively), relative standard deviation of 2.18%, limit of detection of 0.071 µg/mL, and limit of quantification of 0.237 µg/mL. The quantification results showed that major variety of Oriental tobacco leaves had labdanoids except for Izmir (Turkish Oriental tobacco). Although the amount of total labdanoids differed by varieties, the composition ratio of labdanoids showed a similar pattern through varieties.