Rosa hybrida L. var. Lửa has been one of the most important roses for a long time and is most often used for ornamental purposes in Sadec city, Dong Thap province. The study aimed to induce variation through in-vitro gamma-ray irradiation in the rose variety ‘Lửa’ for further improvement in rose breeding. In-vitro single node cuttings (25 in-vitro cuttings per treatment with four replications) were irradiated with different doses of γ-rays (0, 5, 10, 15, 20, 25, or 30 Gy) using a ⁶⁰Co source (India) at Da Lat Nuclear Research Institute. The γ-irradiated explants were then cultured aseptically on Murashige and Skoog’s basal medium supplemented with 1.0 mg/L BAP to induce multiple shoots, shoot proliferation, and acclimatization at Division of Vegetables, Flowers and Landscaping of Southern Horticultural Research Institute (SOFRI). The LD₅₀ dose was determined at 20 - 25 Gy treatments and these doses affected the multiplication rate, growth in-vitro, and ex-vitro survival rate. Three types of mutants with altered or novel flower color in comparison to the original flower color were isolated, such as Type 1 with orange-pink (Red 52C), Type 2 with pink (Red 54B), and Type 3 with Red 45AB with Red 54B bicolor.