The present experiment was carried out at the Nursery of Ornamental Plants, Faculty of Agriculture, Minia University, Egypt during the two successive seasons of 2020 and 2021 to study the effect of organic compost and bio fertilizers (EM and/ or yeast) on growth, flowering and chemical compositions of Rudbeckia hirta plant. This species is known as an annual ornamental plant and used as flowerbed, pot plants and cut flower as well as it utilizes as a medicinal plant. This experiment was conducted in a complete randomized block design in a split plot arrangement with 3 replicates with 6 pots in each. The organic compost levels (0, 5, 10 and 15 g/ pot) were the main plots, while the bio fertilizer treatments (0, yeast, EM and yeast + EM) were located in the sub plots, obtained results revealed that the treatment with the mixture of the two bio fertilizers resulted in the best values for the growth and flowering parameters compared to other treatments. Also, the plants that treated with EM were more responsive than those treated with yeast or untreated ones in all studied traits. Moreover, results showed that the plant height, number of days to flowering, number and diameter of inflorescences, length of flower stalk, diameter and fresh weight of flower stalk as well as foliar N, P and K % were positively affected by the different compost and bio fertilization treatments. The combined treatments between EM + yeast at 50 ml/ plant with organic compost at 15 or 10 g/ pot gave the highest values compared to the other treatments in the 1^st and 2^nd seasons for all studied parameters.