The present work deals with the establishment of hairy root cultures from different explants of C. procera using Agrobacterium rhizogenes strain A4. A high transformation frequency (95%) was obtained from leaves followed by cotyledons (81.6%) and hypocotyls (38.3%). Genetic transformation of hairy roots was confirmed through PCR by amplifying a 400 bp fragment of the rolB gene. Hairy roots were highly branched, possessed plagiotropic and rapid growth on hormone-free ½ B5 medium. Ten cardiac glycosides, including calotropagenin, calotoxin, frugoside, coroglaucigenin, calotropin, calactin, uzarigenin, asclepin, uscharidin, and uscharin, based on their specific masses and fragmentation properties were identified in ethanolic extracts of hairy roots by ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry UHPLC/QTOF-MS. This protocol could be used as a powerful tool for large-scale in vitro production of highly valued cardiac glycosides and for further transcriptomics or metabolomics studies.