Abstract Oncidium Golden Anniversary orchid is a hybrid variety from Oncidium spacelatum and Oncidesa sarcatum orchid. The yellow flowers that can bloom twice a year and last up to a month have made them into the market. However, this orchid flower is having difficulty when it requires strong, mature pseudobulbs to bloom. Pseudobulbs store the nutrients absorbed by the roots. Therefore, this research focuses on the roots’ growth in in vitro culture until the acclimatization stage. In this research, different concentrations of Indoleacetic Acid (IAA) with 0.5mg/L, 1.0mg/L, and 2.0mg/L, and different weights of activated charcoal (AC) (1.0g/L, and 2.0g/L) were used as additional rooting growth stimulators. These components had been added in Murashige and Skoog (MS) medium to observe their effect on the root length, number of leaves, and number of roots. The result was recorded every four weeks. After in vitro growth, the orchids were acclimatized for a month to observe its survivability rate. Based on the result, treatment 10 with 0.5mg/L IAA and 2.0g/L AC gives the highest number of leaves, which is 9.72 ± 1.74. Moreover, the number of roots gained rapid growth under treatment 2 with 0.5mg/L IAA by 9.82 ± 3.45. Furthermore, the length of roots increased when applied to treatment 3, which contains 1.0mg/L IAA, which gives the longest roots of 93.95 ± 53.7mm. Under acclimatization stages, treatment 2 with 0.5mg/L gives the highest survivability rate (100%). In conclusion, the addition of IAA and activated charcoal has a positive effect on the growth of Oncidium Golden Anniversary orchid , either in the in vitro or acclimatization stage.