In the first part of this study we extracted, isolated, and identified the main diterpenoid constituents from the roots of a Central Asian medicinal and ornamental plant--Perovskia atriplicifolia Benth. Eight major nor-abietanoid pigments were obtained using NP silica gel column chromatography and preparative RP-HPLC: cryptotanshinone, 1-hydroxycryptotanhinone, miltirone, 1-oxomiltirone, tanshinone IIa, 1,2 didehydrotanshinone IIa, 1,2 didehydromiltirone, the non-quinone diterpenoid - arucadiol, as well as rosmarinic acid as a main phenolic compound. Secondly, we used the obtained compounds for fast and selective determination of the main diterpenes present in P. atriplicifolia root extract. After extraction with n-hexane, the quantitative analysis was carried out by LC-MS/MS with a triple quadrupole (qQq) mass detector without any prior clean-up step. Identification of the diterpenes was confirmed by multiple reaction monitoring (MRM) using the most representative transitions from the precursor ions, while the most sensitive transitions were used for quantification in a 19-minute run. Most of the isolated and analyzed compounds had not been previously reported from this species. This easily cultivated plant is a promising source of several pharmacologically valuable abietanoid diterpenoids.