This work was carried out during two successive seasons of 2016 and 2017 in the Experimental lathe house of Horticulture Dept., Faculty of Agric., Benha University, Kalubia Governorate, Egypt to study the effect of paclobutrazol, cycocel and pinching treatments on growth, flowering and chemical composition of potted Tabermaemontana coronaria plants. After one month from repotting process (March 1st during the two seasons), the plants were arranged into two groups; the first one was lifted without pinching, while the second group was subjected to pinching treatment by removing 1cm from the seedling top, then all plants of the two groups were subjected to three sprays with paclobutrazol at 0.0, 30, 60 and 90 ppm and cycocel at 0.0, 1000, 2000 and 3000 ppm plus tap water as control at one month intervals. The obtained results showed that all pinched plants received growth retardants treatments were shorter than those received growth retardants without pinching in the two seasons. Besides, all pinched plants received growth retardants treatments have more branches/plants, leaves number/plants, leaf area/plant, fresh and dry weights/plants than those received growth retardants without pinching in the two seasons. Anyhow, the highest valued branches/plants, leaves number/plants, leaf area/plant, fresh and dry weights/plants were scored by those subjected to pinching treatment and sprayed with pp333 at 90 ppm in the two seasons. Moreover, all studied treatments of paclobutrazol, cycocel and pinching increased the chemical composition content of Tabernaemontana coronaria plants in the two seasons.