The study aimed to define the best conditions to conduct germination tests for Ormosia arborea seeds and assess the viability of seeds using the tetrazolium test. The germination tests were conducted at temperatures of 10, 15, 20, 25, 30, and 35 °C and alternating temperatures of 20-30 °C, in the presence or absence of light. For the tetrazolium test, seeds were immersed in tetrazolium solution 0.075%, at 35 °C for three hours, and then the viability was evaluated. It was verified that the seeds did not present absolute photosensitivity. The tetrazolium test was effective in separating the seeds into two categories concerning seed viability, viable and nonviable. It was concluded that O. arborea seeds germinate in the presence or absence of light in a wide range of temperatures. Temperatures of 25 and 30 ºC and alternating temperatures of 20-30 ºC are indicated to conduct germination tests. The tetrazolium test was effective in assessing seed viability.