Aim: To investigate the effects of commonly used intravitreal steroids on survival and proliferation (namely, proliferation index) of ciliary body-derived mesenchymal stem cells (CB-MSC).Methods: CB-MSCs were isolated from newborn rats' eye, and they were expanded in the medium. Commonly used intravitreal steroids such as dexamethasone (Dex) and triamcinolone acetonide (TA) were added into the medium at commonly used concentration in clinical practice (0.1mg/mL) and at lower concentration (0.01mg/mL). Proliferation indexes of CB-MSCs were analyzed with the xCELLigence system at nine consecutive times (at 3rd, 6th, 21th, 30th, 45th, 60th, 75th, 90th and 100th h).Results: Both TA and Dex at both 0.01mg/mL and 0.1mg/mL concentrations had negative effect on proliferation indexes of CB-MSC. Although negative effect of TA on proliferation index of CB-MSC at both concentrations was not statistically significant, statistically significant negative effect of Dex at 0.01mg/mL concentration started 60th h (p=0.017) and 0.1mg/mL concentration started 30th h (p=0.014).Discussion: Even therapeutic doses of intravitreal corticosteroid agents might have negative effects on limited numbers of stem cells. Especially, Dex caused statistically significant toxic effects on CB-MSCs even at lower concentrations of those used clinically. These novel findings deserve further in vivo investigations.