Transcriptional response of grapevine (Vitis vinifera L.) VvOSM1 has been investigated in Baladi and Halawani cultivars and B41 rootstock grapevine leaves, under salt stress [(0, 1, 2 and 3 dS/m of sea water (SW)] treatment after 1, 3 and 5 days of exposure. Real-Time PCR (RT-qPCR) technique has been employed to investigate VvOSM1 gene expression in two cultivars and one rootstock grapevine. Data revealed that the VvOSM1 transcription level increased for the two cultivars as the applied salt concentration increased from 1 to 3 dS/m, and also with salt exposure time from 1 to 5 days; expect for Baladi. Overall, transcript expression was higher in the examined cultivars compared to the B41 rootstock. Whereas, with a prolonged time exposure up to 3 days, VvOSM1 gene showed up-regulation in Halawani cultivar and down-regulation in Baladi cv. and B41 rootstock. Thereby, RT-qPCR technique could be used as a potential tool for VvOSM1 transcriptional response in grapevine breeding programs.